Articles tagged with: Mine Engineering

Mining Under Lakes – Part 1: Examples

Mining Under Lakes
Springpole Project

Springpole Project

I recently saw an investor presentation from First Mining Gold about their Springpole Project. The situation is that their open pit is located within a lake and will require the construction of a couple of small cofferdams to isolate the pit area from the lake. The concept is shown in this image.
Over the last couple of years I have been involved in a few early-stage studies for mining projects in which nearby bodies of water play a role in the design.    In Canada’s north there are thousands of lakes and rivers, so its not surprising to find mines next to them.
That got me thinking about how many other mines are in the same situation, i.e. projects that may be located very close to, or within, a lake, river, or ocean. Hence I have compiled a short list of a few such mines.
I have been directly involved with some of those in the list, while others are only known to me with limited detail. Some mines I had never heard of before, but their names were provided to me by some Twitter colleagues.
My observation is that building a mine within, or adjacent to, a body of water is nothing new and this has been done multiple times successfully.
Some of these projects may refer to the dams as “dikes”, “cofferdams”, “sea walls” but I assume they are all providing roughly the same function of holding back water for the life of the project.  They are not viewed as permanent dams.
This is Part 1 of a two-part blog post. Part 1 provides some examples of projects where water bodies were involved in the design. Part 2 provides a discussion on specific geotechnical and hydrogeological issues that would normally have to be examined with such projects.

Some Lake Mining Examples

The following are some examples of operating mines involving lakes. I have captured a few Google Earth images, unfortunately some have only low resolution vintage satellite imagery.

Diavik Diamond Mines, NWT

This is a project I was working on with in 1997 to 2000 while it was still at the design and permitting stage.  My role focused on pit hydrogeology and geotechnical as well as mine planning.
The project would require the construction of three dikes in sequence to mine four lakebed kimberlite pipes.
The three dikes were named after the associated kimberlite pipe being mined inside it; A154, A418, and A21.
The first dikes were built in 2002 and the last dike (A21) was completed in 2018.
The total dike length for the three dikes is about 6.2 km.
For those interested in learning a bit more about Diavik, I have posted an earlier article about the open pit hydrogeology there, linked to at " Hydrogeology At Diavik – Its Complicated".
Diavik mines

Gahcho Kue, NWT

This is a DeBeers diamond project was built in 2016 and required the construction of several small dikes to allow access for open pit mining.    The photos show the pre-mining situation and the site as it is today.   One can see the role the lake would play in the site layout and the need for multiple small dikes.
Gahcho Kue diamond mine

Meadowbank, NWT

This is an Agnico-Eagle gold mining operation built in 2010 that required a cofferdam to be built around one of their open pits (see image).
The total dike length is about 2000 metres.   I don't know much more about it than that unfortunately.
Meadowbank Mine

Cowal Gold Mine, Australia

Yes, a lake in Australia ! This is a former Barrick operation, now owned by Evolution Mining, and is another example where the mine is located within the shoreline of a lake (Lake Cowal).    I don't know much about this, the name was kindly provided to me by a colleague.
The total dike length appears to be about 3000 metres.
Cowal Gold Mine

Rabbit Lake Sask

The historical Rabbit Lake uranium mining operation required the construction of cofferdams around a few of their open pits.  They are now reclaimed and flooded.
Rabbit Lake uranium

St Ives Gold Mine, Australia

This is a unique situation in that several pits are located within an ephemeral (intermittent) salt lake and dikes were required to prevent pit flooding during wet season.
St Ives gold mine

Some River Mining Examples

The following are some examples of operating mines involving rivers.  Rivers provide a somewhat different design challenge since they have flowing water, who's volume and velocity may change seasonally.    Constrictions in the river created by the dike itself may increase the flow velocity and erosion potential.

Gorevsky Mine, Siberia

This lead-zinc operation has an orebody that extends into the Angara River.
This mine has built a fairly large cofferdam into the river, and is currently mining a large pit within it.  The total cofferdam length appears to be about 4000 metres.
It would be interesting to see how close the pit will get to the cofferdam.   We'll check back in a few years.
Gorevsky Mine

BHP Suriname Bauxite Mine

This is a project I was involved with several years ago.  The bauxite deposit extends beneath the Suriname River and the goal was to mine as much ore as possible.
Given the flow rates in the river, especially during the wet season, it would be difficult to maintain a cofferdam out into the river.
The shoreline overburden consisted of sands and soft clays, so the decision as made to construct a sheet piling wall along the river bank to protect the pit from river erosion.   This was mined out successfully and eventually reclaimed.
Suriname Bauxite Mine

McArthur River, Australia

In situations where the river (creek) is small enough and the topography allows, one can divert the entire river around the mine.
There are several examples of this in Canada and elsewhere.  Here’s the McArthur River lead-zinc mine in Australia, where they channeled their small river around the open pit.
McArthur river diversion

An Ocean Example

There are some examples of mining near the ocean. These operations may need to deal with large storm water level surges and large tidal fluctuations.   The Island Copper Mine on northern Vancouver Island is an example where they mined close to the shoreline but not actually into the ocean (as far as I am aware).

Cockatoo Island Mine, Australia

This interesting iron ore mine has an ore zone that dips 60 degrees, is 35 metres wide, with a strike length of more than one kilometre.
A sea wall was constructed to prevent any tidal water from entering the open pit that was to be mined, with reportedly high tidal fluctuations there.
Cockatoo iron mine

Conclusion

As one can see, the idea of mining into a body of water is nothing new.   Its not a preferred situation, but it can be done economically and safely.   The technical challenges are straightforward, and engineers have dealt with them before.  However there also are instances where the design could not economically address the water issue, and thus played a role in the mine not getting built.
If you know of other mines not listed above that have successfully dealt with a water body, please let me know and I can update this blog post.
This concludes Part 1.  Part 2 (to be publish in a couple of weeks) will discuss some of the design issues that engineers need to consider when building a mine in these situations.

Pantai Remis tin mine

Finally, the worst-case scenario is shown in this grainy video of a tin mine (Pantai Remis Mine) pit slope failure.  It seems they mined too close to the ocean.  Watch to the end, its hard to believe. Its looks like something out of a Hollywood disaster movie.

 

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Steeper Pit Slopes Can Save Money

We likely have all heard the statement that increasing pit wall angles will result in significant cost savings to the mining operation.
What is the potential cost saving?
The steeper wall angles reduce waste stripping volumes, which also provide other less obvious benefits.
I was recently in a situation where we undertook some comparative open pit designs using both 45 and 50 degree inter-ramp angles (“IRA”). I would like to share some of those results and discuss where all the benefits may lay.

Comparative Pit Designs

In this project, four separate open pits were designed with 45 and 50 degree IRA’s in an area with hilly topography. Some of the pits had high walls that extended up the valley hillsides. Its not hard to envision that waste stripping reductions would be seen along those areas with steepened walls.
The results of applying the increased  inter-ramp angle to each of the four pits is shown in the Bar Chart. Note that the waste reduction is not necessarily the same for each pit.  It depends on the specific topography around each pit.
However, on average, there was an overall 15% reduction in waste tonnage.
The Table shown below presents the cumulative tonnage for all four pits. The 50 degree wall results in a waste decrease of 25.4 million tonnes (15%), with a strip ratio reduction from 5.8:1 to 5.0:1.
There is also a very minor decrease in ore tonnage. This is because the 50 degree slopes did lose some ore behind the walls that is being recovered by the 45 degree slope.
In both scenarios the project life would be about 10 years at an assumed ore processing rate of 3 Mtpa.

4 Positive Impacts of Steeper Walls

In general one can typically see four positive outcomes from adopting steeper pit walls. They are as follows:
1. Cost Savings: The waste tonnage reduction over the 10 year life would be about 25.4 million tonnes. At a mining cost of $2.00/tonne, this equates to $50.8 million tonnes spent less on stripping. This could move the project NPV from marginal to profitable, since most waste is normally stripped towards the front part of the mining schedule with less discounting.
The next time you are looking at the NPV from an open pit project, take a quick look to see if the pit slope assumptions are conservative or optimistic. That decision can play a significant role in the final NPV.
2. Equipment Fleet Size: Over the 10 year life, the average annual mining rate would range from 20.5 Mtpa (45 deg) to 18.1 Mtpa (50 deg). On a daily basis, the average would range from 56,100 tpd (45 deg) versus 49,700 tpd (50 deg). While this mining rate reduction is not likely sufficient to eliminate a loader, it could result in the elimination of a truck or two.   This would have some capital cost saving.
3. Waste Dump Size: The 15% reduction in the waste tonnage means external waste dumps could be 15% smaller. This may not have a huge impact but could be of interest if waste storage sites are limited on the property. It could have a more significant impact if local closure regulations require open pit backfilling.
4. Pit Crest Location: The steeper wall angles result in a shift in the final pit crest location. The Image shows the impact that the 5 degree steepening had on the crest location for one of the pits in this scenario.
Although in this project the crest location wasn’t critical, there are situations where rivers, lakes, roads, mine facilities, or public infrastructure are close to the pit.  A steeper wall could improve ore recovery at depth while maintaining the same buffer setback distance.

Conclusion

Steeper pit walls can have multiple benefits at an open pit mining operation. However, these benefits can all be negated if the rock mass cannot tolerate those steeper walls. Pit wall failures could be minor or they could have major impacts. There are the obvious worker safety issues, as well as equipment damage and production curtailment concerns with slope failures.  Public perception of the mining operation also comes into play with dangerously unstable slopes.
Steepening of the pit walls is great in theory, but always ensure that geotechnical engineers have confirmed it is reasonable.
It is relatively easy to justify spending additional time and money on proper geotechnical investigations and geotechnical monitoring given the potential slope steepening benefits.
When designing pits, there is some value in looking at alternate designs with varying slope angles to help the team understand if there are potential gains and how large they might be.
In closing, I previously wrote a related blog post about how pit walls are configured to ensure safe catch bench widths and decisions as to whether one should use single, double, or triple benching. That earlier post can be read at this link. Pit Wall Angles and Bench Widths – How Do They Relate?
Feel free to share your personal experiences if you are aware of other benefits (or even downsides) to steeper pit walls that I did not mention.
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Games People Play

Are you a board game player?  Personally I am not.  However I understand there is a huge board game community out there. These game enthusiasts meet in small coffee shops and attend large gaming conventions. I read that 35% of Americans say they play board games several times a month. Think about how many board games you may have laying around in your own place, even if you’re not a hard core gamer.
Recently an avid board game player sent me an email asking if I was aware that there several mining related games. That was a surprise to me. Who would create a board game about mining and for what demographic market?
Curiosity took over and I had to check out the links sent to me on the Board Game Geek website. Here’s a few of the games and what they do.   Now that Germany may be moving back into coal, the first three games may come back into fashion.  The 4th game listed is a bit of a head scratcher.

A few of the mining board games

Game 1: Haspelknecht: The Story of Early Coal Mining (2015)
This game is part of a coal-mining game trilogy created by Thomas Spitzer in Germany. The players take the role of farmers with opportunities to exploit the presence of coal in the Ruhr region of Germany. During the game, players acquire knowledge about coal, extend their farms, and dig deeper in the ground to extract more coal.
Players must select the correct tasks while being mindful of quickly accumulating pit water, for it can stall efforts and prevent extraction of coal.  The game info link is here.
Game 2: The Ruhr: A Story of Coal Trade (2017)
In the second game of Spitzer’s trilogy, you are still in the Ruhr region in the 18th century, at the beginning of the industrial revolution. The Ruhr river presented a transportation route from the coal mines. However, the Ruhr was filled with obstacles and large dams, making it incredibly difficult to navigate.
The players transport and sell coal to cities and factories along the Ruhr river in the 18th and 19th centuries. In the beginning, players have access only to low value coal but can gain access to high value coal. The players also build warehouses, locks, and export coal to neighboring countries in the pursuit of the most points.
The info link is here.
Game 3: Schichtwechsel: Die Förderung liegt in deiner Hand (2021)
This game may still be in German text only. Players are the administrator of a coal mine, and experience competition while living through a piece of Ruhr Valley history.
They bring coal and overburden from underground to the surface, let the miner go through a “shift at the colliery”, produce coke, or build the typical colliery settlements.
The info link is  here.
Game 4: The Cost (2020)
This game takes on a more negative view of the mining industry. It is described as “A bold take on the economics in the brutal industry that is asbestos.” The game players assume the role of a global asbestos company.
Players make their fortune in mining, refining, and shipping. Whoever ends the game with the most money wins. The last part of the description is the gem “When players mine or refine asbestos, they must choose to either maximize profits for short-term gains or sacrifice their hard-won money to minimize deaths, thus sustaining the industry.” That’s every mining executive’s dilemma; profits or deaths.   The info link is here.
Some of these game boards look more complicated than the actual industry. To find other games you can go to the Board Game Geek website and search for different themes. Most mining games listed there are not realistic but are more about dwarves mining gems or they just have an activity called “mining”.   Here’s one called Copper Country.

Free Excel Mining Game

In 1983 my brother, at the age of 10, got his Commodore 64 computer and was eagerly learning to program in BASIC. He was always looking for ideas on what he could write programs about. I had graduated from McGill in Mining Engineering a few years earlier, so I suggested he write a simple computer game about mining as his project.
I provided him with the logic and in no time he had it written and functioning. That game is long gone, likely at the bottom of a landfill stored inside the chips of his Commodore 64. Some 40 years later, my brother is still coding as a software development manager. I guess I managed to convince him the mining industry wasn’t a career path.
Over the last few months I decided to learn VBA (Visual Basic for Applications). VBA is a programming language the works with Microsoft Office products, mainly Excel.
I always enjoyed programming. In university we wrote FORTRAN programs using stacks of punch cards to feed the machine the code. I had also learned the BASIC language, from my brother’s VIC 20 and Commodore computers.
A good way to learn something is to watch a few pf the many tutorial videos on YouTube. An even better way to learn VBA is by taking on an actual coding project from scratch. So, what worked 40 years ago, would work again. Rather than write something useful, I decided to re-write the mining game from 1983, albeit enhanced with the Excel application capability and more years of personal mining experience.
This coding process would force me to learn how to write code, figure out logic, create loops, if-then statements, and handle debugging. Already knowing Excel makes the entire process easier.  Combining Excel functionality with VBA delivers capabilities that would have been difficult to do in BASIC alone.  Note: It appears that BASIC is no longer in use, having been replaced by Python as the preferred programming language.

Download it.. if curious

If you are curious about the capability of VBA, the Excel mining game can be downloaded. A descriptive overview of the game is included in the PDF file at this link.

Junior Mining CEO game screenshot

The very simple game is called Junior Mining CEO. The object is to find gold, raise the share price, and not go bankrupt given the pitfalls that often befall the mining industry. The input parameters have a lot of optionality, although I have protected the macro code itself for this edition. You can borrow money and issue equity to fund your mining activity.
The Excel file can be downloaded at this link. The was written using Excel 365 but it may also work on older versions of Excel.
You will first need to save the game to your computer to run the macros. Since there are macros, many computers will disable such Excel files because they can contain viruses. You may need to toggle the file Properties in File Explorer to unblock the file to allow the macros to run.
Is there a junior mining corporate sponsorship opportunity here? Sure. For a small fee, I will add your company logo to the game and pre-set all the input parameters so that everyone is a big winner all the time.

Conclusion

As mentioned in a blog from a few months ago, “ A Junior EIT Mining Story” some gamification of mining may help introduce and educated people on the industry. Augmented reality (AR) and Virtual reality (VR) are both technologies that can be used to help reach out to the younger generations (I’m not talking about investor outreach).
How about a new board game that does to mining what Monopoly did to real estate investing? Look at real estate prices today, no doubt being influenced by everything we learnt playing Monopoly as kids.
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Clays and Mining – Friends or Foes?

Overburden is a generalized termed used to describe unconsolidated material encountered at a mine.  It can consist of gravels, sands, silts, and clays and combinations of each. Usually overburden is not given much focus in many mining studies. Very often, the overburden as a unit, is not adequately characterized.
This blog will explain why proper characterization can be an important issue,  particularly the clay component.
I also want to share some personal mining experiences with clays, all types of clays.  There is more to them than meets the eye; a fact often not apparent to those involved only in hard rock mining.
Clays have unique geotechnical properties that can make for challenging situations and require special consideration in project design.   Many simply view clay as a sticky cohesive material – no big deal. So let’s examine this a bit further. I tried to avoid geotechnical lingo where possible, since this blog isn’t being written for geotechnical engineers.
There are several types of clays, or clay-like materials that can be encountered in mining. Here are the ones that I have been lucky (or unlucky) enough to have dealt with over the years.
  • Normally consolidated clays
  • Over-consolidated clays
  • Sensitive (or quick) clays
  • Swelling clays
  • Saprolite clays
  • Kimberlite clays (muds)

What are the challenges?

Each of the clays listed above can be found in different locations, have unique properties, will behave differently, and can create specific mining challenges.   Clays can also cause problems in process plant circuits, but that is a subject outside my area of expertise.

Normally consolidated clays

These are the clays most people are familiar with, i.e. a sedimentary deposit of very fine particles that have settled in a calm body of water.   Normally consolidated clays are generally not a problem, other than having a high moisture content.  As such, they can be very sticky in loader buckets, truck boxes, and when feeding crushers.
When wet, they can become sloppy and difficult to handle efficiently.  They can creep and run when placed into waste dumps.  For these reasons, engineers must be aware if a large proportion of the overburden will consist of clays so they can avoid surprises.

Over-consolidated clays

These clays have undergone greater vertical compression in their history than in their current condition.  For example, perhaps they were once pre-loaded and compressed by a mile of glacial ice sheet during an ice age, which has subsequently melted.
Clays in general consist of very fine plate like particles, as shown in this sketch.   In over-consolidated clays, these particles have been flattened and tightly compressed as in the right image.   The result is that the clay may be dense, have a good cross bedding shear strength, but very low shear strength along the plates.  This characteristic is analogous to the lubricating properties of graphite, which is facilitated by sliding along graphite plates.
My experience in working with over-consolidated clays was at the Fort McMurray oil sands mining operations.  In that region the Clearwater clays formed part of the overburden sequence above the oil sands.  Stripping these clays with trucks and shovels was not exceptionally challenging.  They had low moisture content and were stiff.   The challenge really came when needing to build on top of them, for example building a waste dump or tailings dam.
The cross-bedding shear strength was good, with peak friction angles exceeding 25 degrees.  However after any creep or deformation, the peak shear strength was gone and the residual friction angle would now control stability.   The residual friction angles could drop as low as 6 degrees (very weak) and, upon surcharging the clay could maintain high internal pore pressures.   Due to these factors it was not uncommon to see tailings dams or waste dumps with 15:1 (H:V) downstream slopes.  This compares to the 3:1 slopes one may normally see at hard rock mine sites.
Building a 15:1 dam or dump is much less volume efficient than building a 3:1 embankment.  It also doesn’t take much instability to cause an embankment to creep along a foundation with only a 6-degree friction angle.  Hence the over-consolidated clays presented a unique engineering challenge when working in the oil sands.

Sensitive (quick) clays

Referring to the clay particle sketch shown above, quick clays represent a card house structure (on the left image).  These clays were often deposited in a quiet marine environment, where electrical charges prevented the clays from settling uniformly.  Instead, the clay particles tend to stack up like a house of cards.  The large void spaces are filled with water, whereby moisture contents can exceed 100% by weight.
When these clays are disturbed by vibration or movement, the house of cards structure collapses.  Combined with the excess void water, these clays will flow…. and flow a lot.   This video shows a slope failure in quick clays in Norway.  Try to stop that failure once it has initiated.
My experience with sensitive clays was at the former BHP bauxite mining operations along the northern coast of Suriname.   There were Demerara clay channels up to 20m thick over top of many of their open pits.   The bucketwheel excavators used for waste stripping would trigger the quick clay slope failures, sometimes resulting in the crawler tracks being buried and unfortunately also causing some worker fatalities.
I recall walking up towards a bucketwheel digging face as the machine quietly churned away.   About 70 metres from the machine, we would see cracks quietly opening all around us as the ground mass was starting to initiate its flow towards the machine.   Most times the bucketwheel could just sit there and dig.  Instead of the machine having to advance toward the face, the face would advance towards the machine.
To address the safety issue, eventually mine-wide grids of cone penetration tests were used to define the Demerara clay channels.  Dredges were then brought in to remove these channels before allowing the bucketwheels to strip the remaining sands and normally consolidated clays.

Swelling clays

In some locations, mines may contain swelling clays.  The issue with these clays is that they can absorb water rapidly, swell by 30%, and become extremely soft to operate on.  If they form part of the ore zone and find their way to the tailings pond, one may find they don’t want to settle out in the pond. Water clarification and clean water recycle to the plant can become an operational issue.   Mineralogy tests will indicate if one has swelling clays (smectites, montmorillonites, bentonite).  The swelling clays do have a functional use however, discussed later.

Kimberlite clays (muds)

The formation of the diamond deposits in northern Canada often involved the explosive eruption of kimberlite pipes under bodies of water. The lakebed muds and expelled kimberlite by the eruption would collapse back into the crater, resulting in a mix of mud and kimberlite (yellow zones in the image).   This muddy kimberlite could be soft, weak, and difficult to mine with underground methods.
Normally as one descends deeper into the kimberlite pipe,  the harder primary kimberlite dominates over the muddy material.   An upside is that the muddy kimberlite can be scrubbed fairly easily during processing, with the very fine clay particles being washed away.

Clays can’t be all bad?

Encountering clays at a mine site can’t be always negative?  There must be some benefits that clays can provide?   Well there are a few positive aspects.

Saprolite clays 

At many tropical mining operations (west African gold projects for example) the upper bedrock has undergone weathering, resulting in the fresh rock being decomposed into saprolite.  This clay-rich material can exceed 50 metres in thickness, can be fairly soft and diggable without blasting.   This is an obvious mining cost benefit.
As well, grinding circuits can easily deal with saprolite.  For example, if a 1000 tpd grind circuit is designed for the underlying deeper bedrock, it may be able to push through 1400 tpd of saprolite.   This would yield a 40% increase in mill throughput for little added cost.  This will boost early gold production.  However as the blend of saprolite to fresh rock declines over the years as the pit deepens, the plant throughput will decrease to the original design capacity.
One concern with saprolite sometimes is its sticky nature.   A truck load of saprolite ore dumped on a crusher grizzly may just sit there.  Possible some prodding or water flushing may be required to get it moving.  Nevertheless, this is normally an easily resolvable operating issue.

Clay core dams

One of the ways miners build water retention or tailings dams is to use mined waste rock.   The issue with this is that a dam built solely with waste rock will leak like a sieve, which can lead to piping failure.  One solution is to build an internal clay core in the center the dam to act as a seepage barrier.   Having on-site access to good quality clean clay fill is a benefit when such dams are required.   If the clay fill isn’t available at site, then more complex synthetic liners or internal seepage control measure must be instituted.
Compacted clay fill can also be used as a pond liner material for water retention ponds.
One can also purchase rolls of geosynthetic clay liners (GCL), whereby a thin layer of dried swelling clay is encapsulated between two sheets of geotextile.  Once the liner is laid out and re-hydrated with water, the clays swell and will act as an impervious liner.   The installation approach is somewhat simpler than for HDPE liners and such liners can be self-healing if punctured.  A downside is that the transport weight of these GCL liners can be significant.
See, there are some positives with having clay at site.

Conclusion

All clays are not the same.  The mining of clays can create unique challenges for mining engineers and operating personnel.   Whenever I see study happily mention that their open pit mine waste consists of “free digging overburden”, I say to myself “Be careful what you wish for”.
One must ensure that the overburden is properly characterized, even though it may be viewed as an unimportant or uninteresting material.  Determine whether it consists of gravels, sands, silts, tills, or clays, or combinations thereof.   It can make a big difference in how it is mined, disposed of, and whether it can have any secondary uses on site.  In many studies that I have reviewed, the overburden tends to be forgotten and does not get the technical respect it deserves.
Please feel free to share any thoughts on your experience in working with clays.
We had to build mine haul roads across large swamps underlain by soft clays.   One option was to use geo-textiles or swamp vegetation to assist us.  Another option was to place the sand fill hydraulically.  You can read how we did this at the following blog post “Using Pumped Sand to Build Mine Roads“.
Note: You can sign up for the KJK mailing list to get notified when new blogs are posted.   Follow me on Twitter at @KJKLtd for updates and other mining posts.
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A Junior EIT Mining Story

We know the mining industry is having trouble attracting talent in all sorts of disciplines, including operations, technical, and supervision. Industry people have no shortage of ideas (right or wrong) on how this issue can be addressed in the future. Myself…I don’t really have any good suggestions.
Not long ago I was speaking with a 2020 graduate mining engineer (EIT = Engineer in Training). During our conversation, I was curious to know what attracted him to the industry and if he had any advice on how to reach out to others in his age group. I asked if he was willing to share his thoughts on my blog site. After all, who better to hear from than a recent graduate. He said “yes”, so for your interest, here is his story and his thoughts. (I decided to leave his name out of this article although he was not insisting on anonymity.)

So here’s the story (in his words)

Mining has been a part of my life for as long as I can remember. Being born in Sudbury, many of my family members have been, or are currently involved, in mining through a variety of occupations, including my father who I idolized. However, I never knew my true interest in the industry until my 11th-grade technology class. I had a teacher who was passionate about the mining industry, and he created a project that involved developing a very basic mine design.
Once I started the project, I realized that I enjoyed the design work, as it requires problem-solving which constantly stimulates the mind. After the conclusion of this project, I started doing my own research to expand my knowledge and realized that the financial side of mining had great interest to me as well. This led me at age 16 to start investing in the mining sector, which I continue to this day.
With this developed interest, and my family’s mining history, the decision to study Mining Engineering at Laurentian University was an easy decision. It allowed me to support my hometown and will allow me, given my career ambitions, to put this small school on the international map.
Before my first year of university, I had a summer job tramming at Macassa Mine in Kirkland Lake Ontario, which has been in production since 1933. My mentality was to get the boots on the ground and get the job done, whatever it took (with proper safety precautions of course). Using rail systems, dumping ore cars manually, jackleg drilling, etc. gave me the perspective that mining was archaic, mining was rough, and mining was only about the ounces.
Therefore, when I started the Mining Engineering program at Laurentian University in 2016, I already had a (somewhat negative) preconceived notion of the mining industry, but as my short career progressed, my opinions morphed into something different, something more positive.
Now that I have graduated and been employed for a couple of years, my perspective has changed. However, I feel that the perspective of the general population has not. People within mining have a (positive) bias and realize its importance in our everyday lives. This is showcased in the famous saying “if it is not grown, it is mined” and I believe that to get the industry to progress at an even faster rate, we need to get everyone on board.
It cannot be an industry that just takes from the Earth, it needs to be seen as one that values sustainability, supplies the world with required goods, and creates jobs with high employee satisfaction. Although this has started with companies taking more of an interest in stakeholder value and employee job satisfaction, based on my limited years in the industry, there is still lots of room for growth.
To change the negative view around mining, I believe the main focal point should be electric equipment and the ability for remote operation/work. With all this newly developed technology at our fingertips, I know that future operations will be safer and more sustainable, which should be better portrayed.
The battery-electric equipment will surely increase employee satisfaction since I know firsthand that one of the worst feelings as a worker is to have a scoop operating in a heading that is already 25+ degrees. It will also create more sustainability since the industry can transition from being reliant almost solely on fossil fuels.
In addition, I believe that remote equipment operation is not being used to its full capacity or explained to the younger generation. Right now, there has been equipment running in Canada that was operated in Australia. What is stopping mines from having equipment operators all over the world in urban office spaces or out of their own homes? I believe that for a company to visit a high school, or even a trades school, to sell the idea that you can operate a massive piece of equipment from the creature comforts of home, almost like a real-life video game, would be quite compelling to this audience.
Even creating a mining simulation video game where you can run through a story of being a manager, excavator/scoop operator, truck driver, etc. would get the thought of mining brought into the coming generations at a younger age. This would increase the talent pool from the more typical operator because more and more youth are getting skilled at remote operation through video games due to their increased screen time.
Not only equipment operators, but technical staff could be made fully, or partially, remote. When I describe my job to my (non-mining) peers, many are interested since mining is a fast-paced, stimulating, and rewarding industry.
But as soon as I describe the remote nature of the work, many young professionals, or high school students, get turned away. Therefore, showing teenagers, through school presentations or workshops, that a technical career in mining can lead you down so many avenues (scheduling, ventilation design, drill & blast, etc.) would pique their interest, but I believe adding the ability to work remote, with some occasional travel, would drive the point home.
InternPeople get comfortable and people are afraid to leave home, so selling a career that allows for boundless flexibility in job tasks and constant stimulation while living wherever you desire could allow a shrinkage in the current technical gap.
Overall, the mining awareness and outreach (approach) is still old school. Getting to youth and teenagers through various media streams could be the key to getting engagement from not only the current mining towns but larger urban centres as well.
I mentioned a mining simulation video game previously, but what is stopping us there. Many of my peers, and youth younger than myself, are entering the professions of doctors, lawyers, finance, or criminal investigators.
I might be wrong, but, intriguingly, these are industries are the base professions glorified on TV. Why not develop more TV shows based on mining? I know that there would be some population interest considering many people ask me if the gold we mine underground looks like what comes out of the pans in Yukon Gold Rush.
So do I think the mining industry is archaic…. not anymore.
Do I think the mining industry is rough… somewhat.
Do I think it is only about the ounces…., yes, since a mine will not run any other way.
However, I believe that there has been more importance placed on employee and stakeholder satisfaction. So, with more time, and more engagement from the public of all ages, I think this industry can have a bright future ahead.
END

Conclusion

Firstly, I would like to thank this engineer for taking time to write out his well formed thoughts, and for allowing me to share them.
Many of the mining people I meet are following along in family footsteps. No surprise there. However, the industry cannot rely on that farm system alone. It should be reaching out to broader society, although that may require some out-of-the-box thinking. People’s attitudes and personalities are different today than they were 20 years ago.  Many different doors are being held open as career options.
The discussion above has some interesting ideas from a person who would be the target of outreach efforts. It likely will take more effort than simply telling people “Hey, your iPhone uses metal, therefore mining is good, and you should work in mining”.
This guest blog post is an industry perspective from the view of a young engineer.  If you interested in the perspective from a seasoned engineer who has worked around the globe, check out the book that is described in this blog post “Life as an Engineer – Read All About It“.
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Hard Rock Continuous Cutting – Reducing Drill & Blast

Several years ago I worked in the Saskatchewan potash industry where I grew my appreciation for continuous mining systems. Some of the key benefits were the high productivity per man-hour and the safe operating conditions.  On a 12 hour nightshift, with a crew of 16 people we could mine over 9,000 tonnes of ore.  Productivity is  likely even higher now with the larger machines.   Therefore, since that time, I have always kept an eye out for when similar technology can be applied in hard rock mining.
One of the research areas we are seeing these days is the development of continuous cutting technology for hard rock mine development.  The idea is to replace the conventional drill & blast approach with something more efficient and safer.  No need to deal with explosives, noxious gases, shatter the wall rock, or have personnel scale their way under loose conditions.
Recently I was contacted by someone associated with Robbins asking if I was aware of their MDM5000 mine development technology.  I wasn’t aware of it, but I wondered if there finally is a light at the end of the tunnel.

4-rotor miner

In Saskatchewan potash the entire mining operation relies on track-mounted continuous miner technology.   The miners are connected directly to the shaft area using a network of conveyors, up to 10 km worth of conveyor.
The potash miners are able to undertake both development work and production mining whilst connected to conveyor.
From time to time they will rely on shuttle cars, scooptrams, or grasshopper conveyors for small development tasks. A roadheader may also be available for localized ground stabilization.
All of this mechanical cutting is done in potash (sylvinite rock), considered a soft rock with a compressive strength of 20-40 MPa. For comparison, hard rock can have compressive strengths exceeding 250 MPa.

Two approaches in hard rock

Hard rock piloting trials are underway at a few operations, using different vendors with different equipment.  These trials include companies like Komatsu, Robbins, Sandvik, and Epiroc.  Each are testing their own equipment and cutting technologies.
The hard rock cutting approaches generally fall into two camps.

Roadheader style

There are the track mounted roadheader style cutters, typically with a movable arm used to shape the excavation.  Any excavation shape is possible.

Tunnel Borer Style

Then there are the tunnel borer styles, where the machine propels itself with hydraulic shoes and the opening shape is based on the machine configuration. Normally a circular shaped opening is the result.
The roadheader style cutter is normally restricted to softer rock (< 50 MPa) while the tunnel borer is capable of much harder rock (200-250 MPa).

Robbins MDM5000

One system that peaked my interest is the Robbins MDM5000 because it can both cut hard rock and create a rectangular opening. Speaking with the vendor, this unit uses shoes to propel itself while cutting a rectangular shaped opening about 5m x 4.5m in size (see image).  A rectangular shape is preferred to the circular opening whereby the floor invert must be backfilled to provide a level operating surface.

MDM5000 opening shape

The MDM5000 configuration and advance rate allows the installation of ground support and utilities behind the advancing face.   Water sprays and dust collectors help to maintain visibility and air quality at the working face.
The Robbins unit is best suited for long straight drives although reportedly it can turn curves with 450-m radius.  Tighter turns may be feasibility in the future by tweaking the machine design.   Interestingly driving a drift uphill is easier than driving downhill due to the more efficient cuttings removal capability.
The MDM5000 unit can be linked to a Robbins conveyor system, which includes a head drive and an extensible belt storage unit that can feed out the conveyor belt as the machine advances forward.  This operation is similar to that used in the Saskatchewan potash industry.

Robbins MDM5000

A Robbins machine has been in operation at the Fresnillo mine for several years with favorable results (check out the link here).
One nice thing about disc cutters is that they can accommodate variable rock types (softer and harder) while road headers can be hindered by hard rock zones.  Roadheaders require a bit more consistency in rock quality.
Continuous cutting systems, such as the MDM5000, can be combined with vertical conveying technology, leading to safe and rapid development (>200m per month) in the right situation.

Conclusion

No doubt that we will eventually see more application of hard rock continuous cutting technology in the right situations.  The Stillwater Mine in Montana has been using a Robbins tunnel borer for years for development tasks.
No matter how well these new systems perform, there will still be some limitations.  This means the conventional drill and blast development will always be around.  However, keep your eyes on this mining technology sector as improvements in cutter head design and equipment mobility continue to evolve.
Coincidentally International Mining (Nov-Dec 2021) recently published an in-depth article on the various systems being looked at.  The link is here.

 

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Pit Optimization – More Than Just a “NPV vs RF” Graph

In this blog I wish to discuss some personal approaches used for interpreting pit optimization data. I’m not going to detail the basics of pit optimization, assuming the reader is already familiar with it .
Often in 43-101 technical reports, when it comes to pit optimization, one is presented with the basic “NPV vs Revenue Factor (RF)” curve.  That’s it.
Revenue Factor represents the percent of the base case metal price(s) used to optimize for the pit. For example, if the base case gold price is $1600/oz (100% RF), then the 80% RF is $1280/oz.
The pit shell used for pit design is often selected based on the NPV vs RF curve, with a brief explanation of why the specific shell was selected. Typically it’s the 100% RF shell or something near the top of the NPV curve.
However the pit optimization algorithm generates more data than just shown in the NPV graph.  An example of that data is shown in the table below. For each Revenue Factor increment, the data for ore and waste tonnes is typically provided, along with strip ratio, NPV, Profit, Mining cost, Processing, and Total Cost at a minimum.
Luckily it is quick and easy to examine more of the data than just the NPV curve.

In many 43-101 reports, limited optimization analysis is presented.  Perhaps the engineers did drill down deeper into the data and only included the NPV graph in the report for simplicity purposes. I have sometimes done this to avoid creating five pages of text on pit optimization alone, which few may have interest in. However, in due diligence data rooms I have also seen many optimization summary files with very limited interpretation of the optimization data.
Pit optimization is a approximation process, as I outlined in a prior post titled “Pit Optimization–How I View It”. It is just a guide for pit design. One must not view it as a final and definitive answer to what is the best pit over the life of mine since optimization looks far into the future based on current information, .
The pit optimization analysis does yield a fair bit of information about the ore body configuration, the vertical grade distribution, and addresses how all of that impacts on the pit size. Therefore I normally examine a few other plots that help shed light on the economics of the orebody. Each orebody is different and can behave differently in optimization. While pit averages are useful, it is crucial to examine the incremental economic impacts between the Revenue Factor shells.

What Else Can We Look At?

The following charts illustrate the types of information that can be examined with the optimization data. Some of these relate to ore and waste tonnage. Some relate to mining costs. Incremental strip ratios, especially in high grade deposits, can be such that open pit mining costs (per tonne of ore) approach or exceed the costs of underground mining. Other charts relate to incremental NPV or Profit per tonne per Revenue Factor.  (Apologies if the chart layout below appears odd…responsive web pages can behave oddly on different devices).

Conclusion

It’s always a good idea to drill down deeper into the optimization output data, even if you don’t intend to present that analysis in a final report. It will help develop an understanding of the nature of the orebody.
It shows how changes in certain parameters can impact on a pit size and whether those impacts are significant or insignificant. It shows if economics are becoming very marginal at depth. You have the data, so use it.
This discussion presents my views about optimization and what things I tend to look at.   I’m always learning so feel free to share ways that you use your optimization analysis to help in your pit design decision making process.
As referred to earlier, there is a lot of uncertainty in the input parameters used in open pit optimization.  These might include costs, recoveries, slope angles and other factors.  If you would like to read more, the link to that post is here.  “Pit Optimization–How I View It”.
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Potash Stories from 3000 Feet Down – Part 2

This is Part 2 of my story about working at a potash mine in Saskatchewan. If you haven’t read Part 1, here is the link to it “Potash Stories from 3000 Feet Down – Part 1“.  It’s best to read it first.

Flooded Russian Potash Mine

As mentioned in Part 1, water seepage and potential leaks were always an operational concern. There were essentially two main fears; (i) that a borer would tunnel into an unforeseen collapse zone (i.e. an ancient sink hole) or (ii) that long term deformations in the mine would result in cracking of the overlying protective salt layer resulting in water inflow.
Any time wet spots were seen on the roof, the mining engineers or geologists were called out to take a look.
Sometimes the wet area was due to pockets of interstitial moisture. Other times it might have just been oil from a blown hydraulic hose on the borer. Wet spots all look the same when covered in dust.
Water ingress was such a concern in that an unmined pillar of 100 ft. would be left around all exploration core holes. These 3,000 ft. holes were supposedly plugged after drilling but you could never be certain of that. Furthermore, you couldn’t be certain of their location at potash depth. Hence, we didn’t want to mine anywhere close to them.
The process plant also had several water injection wells whereby excess water was injected into geological formations deep below the potash level. We left a 700 ft. pillar around these injection wells.
Carnallite is a magnesium salt that we encountered in some areas of the mine. It was weaker than the halite, resulting in more rapid room closure and deteriorating ground conditions. It was also hydroscopic and could absorb moisture out of the air. Sometimes we would water the underground travel ways to mitigate dust issues. With the resulting high humidity sometimes the carnallite areas might start to drip water. This resulted in another call to the engineers to come out and investigate.

Working on a production crew brings new learnings.

My period as a production foreman was great. When first assigned to this role, I was less than enthusiastic but when it was over 6 months later, I appreciated the opportunity. As a production foreman, we had a crew of 15 to 20 people responsible for mining 9,500 tons over a 12 hour shift. There was one foreman in the underground dispatch room and one face foreman travelling around supervising the borers and inspecting conveyors.
Ore grade control was a key responsibility of both the borer operator and mine foreman. The goal for the borer operator was to cut the roof even with the top of the high grade potash bed. The goal for the foreman was to ensure the operator was maintaining his goal. However, when looking at the potash face all the beds generally looked the same, especially when they are dusty.

Feel the glow

One key distinction was that the middle low grade bed had a higher percentage of insol clays. It was used as a marker bed. You would take your hardhat lamp and run it down against the wall. In the upper high grade potash bed, the cap lamp would have a halo, not unlike like the glowing salt rock lamps you see in stores. In the marker bed the halo would disappear, like putting a lamp against a rock wall.
Thus using the lamp you could identify the top of the marker bed, which was supposed to be kept 3.5 to 4 ft. off the floor. If borer operators were consistently more than 12 “ inches off optimal level, they could be written up (i.e. reprimanded). This was one of my tasks as foreman and I always hated doing it.
Lasers were used to guide the borer in a straight line but the marker bed was used for vertical control. Nowadays the use of machine mounted ore grade monitors is an option. By the way, if you’re looking at a potash project, be aware of the grade units being reported. A previous blog discusses this “Potash Ore Grades – Check the Units”.
The underground conveyor network consisted of 32” conveyors, feeding onto 42” conveyors, feeding on to 48”or 54” conveyors. Typically the length of the larger conveyors was in the range of a mile (5,000-6,000 ft.). The conveyors were all roof mounted, allowing for easy clean up underneath. Roof mounting was critical. Even some of the 600 hp conveyor drive stations were roof mounted, structure and all.

Conveyors were the reason for my one and only safety incident.

4-rotor side pass

4-rotor borer side pass

First a little background. The underground ore storage capacity at K1 was about 3,000 tons. If the underground bins were filled anytime during a shift, the entire conveyor system would automatically trip off; all 10 miles of it. If you happened to have a mile long conveyor shut off while it was loaded to the brim with ore, good luck starting it up again.
If this happened, there were two choices. You could bring in the operators from the borers to start shovelling off the conveyor until it was unloaded enough to re-start. This option went over like a lead balloon with the crew.
The other not so great option was to use a scooptram to lift the belt counterweight up to reduce the belt tension. This allows the drive pulleys to start spinning. Then by lowering the counterweight back down perhaps the drives can inch the belt along. The idea being that possibly the momentum of the moving mass of potash would keep it moving. The downside is that you could break the belt. There was nothing worse than having to tell the cross shift they have both a stalled conveyor and a broken belt. Have a good shift people.
At 4 a.m. working as night shift face foreman, I knew the underground bins were nearing full. Driving along I saw that the mainline conveyor was full and spilling over the sides. A worst case conveyor shutdown was imminent. I called the dispatch office to ask why he hasn’t been shutting down borers and conveyors but there was no answer.
After several unanswered calls I started to hustle back to dispatch. I remember driving alongside the conveyor thinking “don’t shut off, don’t shut off”. Just then a heavy duty service vehicle pulled out of a cross-cut and I plowed right into it. I wasn’t going very fast (~20 km), but when a Toyota Land Cruiser hits a steel plate truck, the Toyota is the loser. The front end crumpled, and I later was told that there was major frame damage.
I’m not sure why the other driver didn’t see my lights. I’m also certain his lights were not on. Nevertheless, I did get written up for this incident with a reprimand for my personnel file. The reprimander had become the reprimandee. I still insist that the incident wasn’t my fault.
The Land Cruiser laid around the shaft for a few days until it could be hoisted up to surface. Everyone coming on shift got to see it . Once it was hoisted up, it laid outside the headframe for a few more days for all the surface workers to see. Ultimately, this incident resulted in the underground miners giving me the nickname “Crash”.
This is where I’ll end the potash story.

Conclusion

Saskatchewan potash is a unique mining situation. It has its own history and mining method. The people are great and it’s a great place to learn the difference between engineering school and real life.

Mine Engineering Dream Team

By the way, I also learned that small town Saskatchewan loves their senior hockey league (20-30 year age range). The local towns compete all winter; sometimes combatively. It was Esterhazy vs. Langenburg vs. Whitewood vs. Rocanville vs. Stockholm vs. Moosomin.
One of the first questions asked in my job interview at Mosaic was if I played hockey. You see, the ideal candidate for the job would have been an ex-NHL player, preferably an enforcer, who is also a mining engineer. Gotta stack the local team.
If you enjoy reading these types of stories about working as an engineer, there is an entire book on the subject, written by a former colleague of mine.  You can learn a bit more about this civil engineer’s experiences working around the global at this link “Life as an Engineer – Read All About It”

 

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Potash Stories from 3000 Feet Down – Part 1

Mosaic K1 Mine

Between 1985 and 1989 I worked at the Mosaic K1 potash mine in Saskatchewan, Canada.  I had roles that included mine engineer, chief mine engineer and production foreman.   This was relatively early in my work career so it represented an important learning period of time for me.
Each of these roles gave me a different perspective about a mining operation.   In this two part blog, I’ll share some stories relating to the uniqueness of potash mining.
The K1 mine is 15 kilometres outside the town of Esterhazy; about 2.5 hours east of Regina.  The mine is located at a depth of around 3,000 feet below surface, hence the title of this blog.
I will be referring to imperial units in this text because when the mine started production in the early 1960’s the maps and units were imperial and continued on through the 80’s.   At my previous job with Syncrude we used metric units, so it took some time to mentally recalculate back.
Geologically, the province wide Esterhazy Member was being mined, named after the town.  The layer was about 8 ft high.  In other regions of Saskatchewan they are mining a different potash layer (the Patience Lake Member) which is located a few feet higher up. These mines have slightly different mining conditions than we experienced in Esterhazy.  An example of their conditions is shown in the photo, where a parting layer can result in a roof collapse.
The Mosaic K1 and K2 mine shafts are interconnected at depth 6 miles.  The total expanse of the K1 and K2 underground workings probably extends laterally over 18 miles.  Back in the 80’s they said there were over 1,000 miles of tunnel underground and probably a lot more now since the mines are still operating.  There is now a new K3 shaft which allows access to more distant potash reserves.

4-rotor borer

Potash, also termed sylvanite, mainly consists of intermixed halite (rock salt) and sylvite (potash) crystals. There are also minor amounts of insolubles (clays) and sometimes carnallite (a magnesium salt).  Sylvite (KCl) is the pay dirt, salt is the gangue mineral.
The production rooms being mined were about 75 ft. wide and 5,000 ft. long.  That is quite a large span, not likely possible in many other rock types other than salt rock.  Overall, the mine would extract about 40-45% of the potash, leaving behind the rest in the form of large pillars to support the overlying rock mass.

2-rotor borer

The mines use continuous miners or borers. In the 80’s they were Marietta miners and now they use borers from Prairie Machine (read more here).   When I was there they were starting to transition from two-rotor to four rotor machines.   The small machines would carve out ~350 tph, and the large ones could do over ~700 tph.
All borers are directly connected to the massive underground conveyor network that moves the ore from the cutter head to the shaft in a continuous process.
Mining excavates an 8 ft. high room consisting of three layers of interest.  A 4.3 ft. layer of high grade ore, a 1.7 ft. layer of low grade ore, and a 2.5 ft. layer of moderate grade potash.  This adds up to 8.5 ft., so the miners try to take the best 8 feet.  The best head grade would be delivered if the borer cut exactly to the top of the high grade 4.3 ft. seam. One didn’t want to overcut into overlying salt or undercut and leave high grade behind in the roof.  I’ll have more on how grade control was done in Part 2.
The air temperature underground is about 25C, so it’s quite a pleasant short sleeve climate.  Around the cutting face, the electric motors, and cutter head, temps can reach into the high 30 degree range. Hot but better than freezing. The mine was dry with very low humidity.   Hence metal didn’t rust.  However, bring the metal to surface and it would rust in no time.
Potash is termed a plastic rock, in that it will deform slowly under stress.  Hard rock will build up stresses and erupt violently in a “rock burst”.  Potash will go with the flow and deform.  Pillars will compress vertically and expand horizontally.  Room heights can decrease over time as much as 6 inches over several weeks in higher stress areas.
Interestingly when the borer shut down and all was quiet, one could walk to the freshly cut face.   You could hear the potash walls gently crackling like rice krispies, as the potash expanded into the opening.  After all, a few moments earlier the potash was being laterally confined under a vertical stress of 3,000 psi. That confinement is suddenly gone.
Roof closure was always an issue.  In panels that were almost mined out, all the ground stress was being carried by the unmined ground.  When advancing into this ground, roof closure could be so rapid that once a borer finished a 4 to 6 week room, the miner operator would need to cut a few inches off  the roof to get back to the front of the room.  It took a couple of days to get the borer out, rather than during a regular shift.
In very high stress areas you could see the floor heaving up as pillars were compressing laterally. That’s when you really knew that mining panel was done and operations should relocate to a new area.
I recall inspecting some of the very old workings from 20 years past.  The rooms looked like new except the roof had compressed down to 5 ft. in height.   We’d have to drive leaning sideways out of the jeep because the steering wheel was literally scraping the roof.

Flooded Russian Potash Mine

The biggest fear in potash mining is water inflow and mine flooding. There can be a water bearing layer about 50-70 feet above the mining level.  A layer of salt rock separates the two.
If you have groundwater flowing through a dissolvable material, it’s no surprise that the pathway will keep getting larger and larger. That’s why any sign of water seepage is taken seriously and causes the engineering team to leap into action (more on that in Part 2).
At least one potash mine in Saskatchewan has flooded.  A couple of others have come close but have managed to deal with the water inflows.
Barren areas where the sylvite has been leached away and replaced with pure halite are called salt horses.   I never knew why and still don’t.
Exploration core holes could be a mile apart so salt horses would be encountered unexpectedly.  They could be 20 or 2,000 feet in size; you never knew which.   They were a nuisance and an economic penalty.  If you tried to tunnel through them, you would send a lot of uneconomic salt up the shaft to the mill (which they did not like).
Conversely, pulling out and abandoning a room was a painful decision because it took that borer off line for a couple of days to relocate. It’s an unplanned outage, which is not good if another borer happens to be moving at the same time.
On occasion, a borer would abandon the room and move to the next room 50 feet away and could pass by the same area without seeing the salt horse.  Upon reflection, perhaps we should have persevered in the previous room and gone another 20 ft. and we might have been through it.  Often the mill manager hollering about the mill getting too much salt was a deciding factor in whether to abandon a room or keep cutting.
For a year or so,  I also worked as a production foreman.  It was an interesting role. How does a young mining engineer four years out of school tell  guys working underground for 20 years what they need to do?
This also leads to the time when I wrecked a Toyota Land Cruiser underground.   I’ll leave that account to Part 2.  I’ve rambled long enough for today.  You can read Part 2 at this link “Potash Stories from 3000 Feet Down – Part 2″.
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Two Mining Innovations – Load Scanning & Vehicle Tracking

The mining industry is always on the lookout for new innovations as it strives to keep up with other industries.  In that light, periodically I like to highlight new technologies that I become aware of.   I’m trying to help spread the word  about them, which in turn may assist them in their on-going growth and development.
In this article I want to briefly describe two hardware / software companies that are working on technologies related to mine equipment productivity.    In no particular order, the two companies are Loadscan and SedimentIQ.  SedimentIQ is more of a startup than Loadscan which has a longer operating track record.
These technology companies are both targeting the open pit and underground markets, looking to provide simpler and less costly productivity solutions. Their technologies may be well suited for small to mid tier mines that cannot afford or don’t require the comprehensive Minestar type fleet management systems.
For the record, I get no fee or commission for promoting these companies; I just like what they are doing.

Loadscan

Loadscan has been around for a few years, but I only became aware of it recently.  It is a technology that allows the rapid assessment of the load being carried in truck.  It does not rely on the use of load cells or weigh scales to measure the payload.
Instead Loadscan uses a laser scanner and proprietary software to three dimensionally map the surface of the truck payload and then calculate its volume.  The results will indicate how consistent and optimal truck loading is volumetrically.   One can then calculate the payload tonnage by applying a bulk density.
The Loadscan technology will assess whether trucks are being over or under loaded, whether the loads are off-centre, or whether there is excess carryback on the return trip.
Successive truck payloads can be tracked manually or with RFID tags.   A cloud based database and web based dashboard are used to store the data and summarize it. The output can include an image of each individual load.
What is interesting about this technology is that it is simple to install in an operation.  It does not require retrofitting of a truck.
Results are immediate.  Loadscan provided an example where a message readout board can let the shovel operator immediately know how well each truck was loaded, resulting in improved education and better performance efficiency.
One can also assess how much better shovel bucket factors are in well blasted rock versus in blocky rock.
The Loadscan system is already in use in several mines globally.  The vendors can provide more technical  data if you need it.
Their website is https://www.loadscan.com/

SedimentIQ

SedimentIQ is a new smartphone vehicle tracking platform that is trying to establish itself.  Their proposed technology makes use of a phone’s built-in GPS, Bluetooth, and accelerometer to track vehicle operation.  The phone’s sensor can measure vibrations produced by an operating truck or loader.
Vibration is a fingerprint of a vehicle’s activity.  Therefore using machine learning, the SedimentIQ app can produce an “activity score” that decides whether a machine is parked, idling, or performing productive work.  The phone is not connected to the machine diagnostics system, so its very easy to install, only needing a power source.
The system will be able to be used on any vehicle, including trucks, drills, loaders, graders, dozers, etc. The system has the capability to monitor equipment location and speed.
In an open pit environment it uses the phone’s GPS to monitor vehicle location. In an underground setting the phone reads inexpensive Bluetooth beacons mounted along the side walls to track location.
The app will identify delay and downtime based on equipment vibration levels.  The system currently requires no interaction with the operator, working in the background.  Hence it will not identify the cause of delay (i.e. blasting delay, breakdown, inter-equipment delay, etc).  I would expect that in the future they could add a feature for the operator to tag delay types on the touch screen.
The SedimentIQ software will aggregate the cycle time and delay information and upload it in real time to a cloud based database.  A web-based dashboard allows anyone with access to view the real time production data graphically or export it to Excel.
The SedimentIQ platform is less expensive than high end fleet management software.  Although it may not provide all the bells and whistles of the high end software, it may deliver just what you need to monitor productivity in your mining operation.  It relies on relatively inexpensive smart phones that are locked to the application.
I recall as a mining student doing time studies.  I rode the shift crew bus with pencil in hand, timing the travel  from the mine dry to the various shovels to measure start up times.  I recall sitting with a stopwatch timing shovel buckets and truck loading times.  Both of these tasks can be done for every shift, every truck by equipping the crew bus and mine trucks with the SedimentIQ tech.
The platform is currently being tested at a couple of trials mines and the founders are looking for more mines willing to adopt and further refine their technology.  Lets hope they can make a successful go of it.
The website is https://sedimentiq.com/.

Conclusion

Both of these innovative technologies can provide useful information to open pit and underground mine operations.  They are in the growth stage, looking for wider adoption.   Input from users, whether positive or negative, will assist them with on-going development and enhancements. Their websites obviously have more on what their technology offers, including presentations, white papers, and case studies.
It would be nice to meld these two technologies in some way to allow the SedimentIQ cycle times to also track payloads.
Check them out.  Try them out.

 

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