Articles tagged with: 43-101

Climbing the Hill of Value With 1D Modelling

Recently I read some articles about the Hill of Value.  I’m not going into detail about it but the Hill of Value is a mine optimization approach that’s been around for a while.  Here is a link to an AusIMM article that describes it “The role of mine planning in high performance”.  For those interested, here is a another post about this subject “About the Hill of Value. Learning from Mistakes (II)“.
hill of value

(From AusIMM)

The basic premise is that an optimal mining project is based on a relationship between cut-off grade and production rate.  The standard breakeven or incremental cutoff grade we normally use may not be optimal for a project.
The image to the right (from the aforementioned AusIMM article) illustrates the peak in the NPV (i.e. the hill of value) on a vertical axis.
A project requires a considerable technical effort to properly evaluate the hill of value. Each iteration of a cutoff grade results in a new mine plan, new production schedule, and a new mining capex and opex estimate.
Each iteration of the plant throughput requires a different mine plan and plant size and the associated project capex and opex.   All of these iterations will generate a new cashflow model.
The effort to do that level of study thoroughly is quite significant.  Perhaps one day artificial intelligence will be able to generate these iterations quickly, but we are not at that stage yet.

Can we simplify it?

In previous blogs (here and here) I described a 1D cashflow model that I use to quickly evaluate projects.  The 1D approach does not rely on a production schedule, instead uses life-of-mine quantities and costs.  Given its simplicity, I was curious if the 1D model could be used to evaluate the hill of value.
I compiled some data to run several iterations for a hypothetical project, loosely based on a mining study I had on hand.  The critical inputs for such an analysis are the operating and capital cost ranges for different plant throughputs.
hill of valueI had a grade tonnage curve, including the tonnes of ore and waste, for a designed pit.  This data is shown graphically on the right.   Essentially the mineable reserve is 62 Mt @ 0.94 g/t Pd with a strip ratio of 0.6 at a breakeven cutoff grade of 0.35 g/t.   It’s a large tonnage, low strip ratio, and low grade deposit.  The total pit tonnage is 100 Mt of combined ore and waste.
I estimated capital costs and operating costs for different production rates using escalation factors such as the rule of 0.6 and the 20% fixed – 80% variable basis.   It would be best to complete proper cost estimations but that is beyond the scope of this analysis. Factoring is the main option when there are no other options.
The charts below show the cost inputs used in the model.   Obviously each project would have its own set of unique cost curves.
The 1D cashflow model was used to evaluate economics for a range of cutoff grades (from 0.20 g/t to 1.70 g/t) and production rates (12,000 tpd to 19,000 tpd).  The NPV sensitivity analysis was done using the Excel data table function.  This is one of my favorite and most useful Excel features.
A total of 225 cases were run (15 COG versus x 15 throughputs) for this example.

What are the results?

The results are shown below.  Interestingly the optimal plant size and cutoff grade varies depending on the economic objective selected.
The discounted NPV 5% analysis indicates an optimal plant with a high throughput (19,000 tpd ) using a low cutoff grade (0.40 g/t).  This would be expected due to the low grade nature of the orebody.  Economies of scale, low operating costs, high revenues, are desired.   Discounted models like revenue as quickly as possible; hence the high throughput rate.
The undiscounted NPV 0% analysis gave a different result.  Since the timing of revenue is less important, a smaller plant was optimal (12,000 tpd) albeit using a similar low cutoff grade near the breakeven cutoff.
If one targets a low cash cost as an economic objective, one gets a different optimal project.  This time a large plant with an elevated cutoff of 0.80 g/t was deemed optimal.
The Excel data table matrices for the three economic objectives are shown below.  The “hot spots” in each case are evident.

hill of value

hill of value

Conclusion

The Hill of Value is an interesting optimization concept to apply to a project.  In the example I have provided, the optimal project varies depending on what the financial objective is.  I don’t know if this would be the case with all projects, however I suspect so.
In this example, if one wants to be a low cash cost producer, one may have to sacrifice some NPV to do this.
If one wants to maximize discounted NPV, then a large plant with low opex would be the best alternative.
If one prefers a long mine life, say to take advantage of forecasted upticks in metal prices, then an undiscounted scenario might win out.
I would recommend that every project undergoes some sort of hill of value test, preferably with more engineering rigor. It helps you to  understand a projects strengths and weaknesses.  The simple 1D analysis can be used as a guide to help select what cases to look at more closely. Nobody wants to assess 225 alternatives in engineering detail.
In reality I don’t ever recall seeing a 43-101 report describing a project with the hill of value test. Let me know if you are aware of any, I’d be interested in sharing them.  Alternatively, if you have a project and would like me to test it on my simple hill of value let me know.
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Connecting With Investors – Any New Ideas?

I recently read some LinkedIn posts from junior mining executives and IR staff asking for ideas about new ways to engage with investors.  The commonly used ways rely on PowerPoints, webinars, and trade show booths.   However during this Covid-19 crisis, trade shows are no longer an option.  Therefore these face to face discussions with investors will now be missing.  This will impact on the ability of a company to connect with and establish trust with those people.

What else can be done?

Perhaps with technology, like Zoom, one can replicate the personal feel of a trade show booth. One can still have back and forth conversations with investors rather than just doing lecture style webinars.
Free discussion is good in most cases. Letting investors feel they are sitting around a table will give them a better understanding of how management thinks and how decisions are being made.  It will also help them get to know the personality of the management team.
I’m not an IR person but I admire the job they have to do, especially in today’s business environment.  I have recently sat in on several junior mining online webinars.  When listening to the Q&A’s afterwards, it is apparent that many attendees enjoyed understanding the technical aspects of a project.  However they will only get that understanding by asking questions.  Trade show booths gave them that opportunity.

Technology gives some options.  Like what?

Set up regularly scheduled Zoom meetings, enabling investors to have interactive back and forth conversations with management.  Try to avoid long presentations with questions only at the end. Have a moderator review and ask questions as they come in.
Management teams should introduce more than just the CEO or COO.  Include VP’s of geology, engineering, corporate development, from time to time.    Don’t hesitate to let the public meet more of your team.  Trade show booths are often manned by different team members.
Pick different topics for discussion on each conference call to avoid repeating the same PowerPoint over and over again.
Avoid being too scripted.
For example one call could be a fly-around of the property using Google Earth.  Another call could focus on the ore body and resource model.  Another call might discuss metallurgy and the thought process behind the flow sheet. Perhaps discuss the development options you have considered.
None of this information is likely confidential if it has been presented in your 43-101 report.
Companies file highly technical 43-101 reports on SEDAR, but then let the investors fend for themselves.   One could take some online time for high level walk through of the report.  Clearly explain technical issues and how they have been addressed or will be addressed in the future.  This is an opportunity to explain things in plain English, and field questions.
One downside to such calls is if there are significant flaws with a project.  Open discussions may help expose them.   One needs to know your own project well, be aware of all the issues, and have them under control in one way or another.

Conclusion

Better communication with investors can increase confidence in a management team.   Although some investors may not enjoy technical discussions, I think there is a subset that will find them very helpful and interesting.  There will likely be an audience out there.
Mining projects are complex with many moving parts and many uncertainties. Trust and confidence will come if a company is transparent in what they are doing and explain why they are doing it.
The mining industry is looking for new ways to reach out, so it shouldn’t be afraid to try new things. Some management teams will be great at it, others not so much.  Figure out where you fit in.
Unfortunately one of the aspects of trade shows that cannot be replicated is the ability for investors to wander around aimlessly, take a quick glance at a lot of companies, and then decide which ones they want to learn more about.

Warning: zoom bombing

As an aside, if you are using Zoom make sure the host has configured the right settings.  There are instances where anonymous participants can suddenly share their own computer screen, i.e. with questionable videos, to the group.  It’s been referred to as “zoom bombing”.
Read more about how to prevent zoom bombing at the following two links.
https://www.forbes.com/sites/leemathews/2020/03/21/troll-terrifies-zoom-meeting-zoombombing/#2765abfc3e70
https://www.businessinsider.com/zoom-settings-change-avoids-trolls-porn-2020-3
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Consultants Have to Earn a Living Too

The number of independent mining consultants is increasing daily as more people reach retirement age or are made redundant.
Nowadays it seems everyone is gradually becoming a self-employed consultant. Possibly that is because retirees need the money.  Maybe they need something post-career to keep them occupied.
Here are a couple of lesser known ways to generate income for those of you choosing this new career path.
One of these has been around for awhile while the other is relatively new.  I only have personal experience with one of them.

GLG – Give me an hour

GLG (https://glg.it/) is one of several information services that provide short term consulting assignments.  By short term, I mean 1 to 2 hours long.
GLG has been around for many years providing a platform for connecting those seeking information with those who have it.
Typically someone, like an industry analyst, poses a question that gets sent out to relevant experts.
The question could be something like “XX Mining Company owns the Bonanza mine and our client would like to learn more about that operation including reserves and operating costs”.
Anyone who has the requisite knowledge can accept the consultation and submit their credentials for review.  If you’re selected, such consultations take place very soon.  They can be for 1 to 2 hours and pay $200 to $500 dollars.  GLG are very strict that rumors or confidential information are not disclosed during any of the consultations.  Only public information is to be used.
Since I have a background in potash, I am often issued potash industry related requests.  Questions posed might be “Can you describe the Saskatchewan potash industry, including operations, expansions, marketing plans, and operating costs”.  That’s a heck of a lot of information to provide in a 1 to 2 hour time frame for $400.   Likely very few people would possess all of that knowledge.   I assume their approach is to consult with several different experts and eventually piece together the puzzle.
Check out the GLG website. It’s free to sign up as an expert and maybe you’ll get yourself an assignment. I think there is even a reward for referrals (which I assume I will get shortly).

Digbee – What’s wrong now?

Digbee (https://thedigbee.com/) is a relatively new online venture that I’ve not yet used.  It is essentially a due diligence platform where one can hire experts to undertake targeted due diligence studies.
Furthermore any expert can prepare an independent review on a topic of their choice and then offer it up for sale.
The typical report costs $1,640 to $4,680 dollars.   As of March 2020, they have 13 reports for sale and 5 more in the pipeline.  Here’s a brief explainer video from the founder
The report list can be seen at this link.  The reports appear to be focusing on potential technical flaws in a project. Some titles are listed below.
  • Sample recoveries at shallow depths is a concern, this is not helped by the total lack of QAQC data” an analysis of Bomboré ($4,680)
  • Has the extensive testwork at Bomboré finally found an optimum process to proceed to development?” ($4,680)
  • Alpala’s technical merits and compares its cost estimate to other block caving development projects.” ($3,120).
  • Cerro Blanco’s very complicated geology in Guatemala may mean more expensive mining techniques will be required.” ($4,680)
  • Epithermal geologist raises questions on the reliability of the low grade resource at DeLamar.” ($3,120)
  • What impact does serpentinisation have on the confidence of recovered grade at RNC’s Dumont project?” ($4,680)
I’m not sure how many report copies each consultant will be able to sell .  However a click-bait title may help sell at least one copy.  That would be to the company the report is about.   Perhaps major investors or financial analysts will also buy a copy.
So if you have some free time, pick a project that’s on your radar and write a review.   It appears that you’ll get a 50% share of the revenue.    To learn more, read an article at this link.
I’m curious if the Digbee platform will continue to grow.  It’s unique to see independent research identifying potential issues with mining projects. Someone jokingly mentioned that these are the anti-newsletter writers.  I’m also curious to see how long before the lawyers and lawsuits begin to show up.
Given the relatively low price for these reports, I think one might make a lot more money (from TMZ) if one wrote a report titled “Famous Hollywood starlet has scandalous affair with mining company CEO”.

Conclusion

If you’re becoming an independent consultant, check out these two revenue channels.   They are tailor made for our growing numbers.
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Consulting and Stock Compensation

The other day a press release came across my desk with the following title “First Mining Issues First Tranche Of Shares To Ausenco; Pre-Feasibility Study For Springpole Gold Project Underway”.
Reading it further, it was apparent that their study consultant, Ausenco, was being paid in company stock in lieu of cash.  The arrangement included an initial financing of $750k with a further $375k to follow once the pre-feasibility study was 75% complete.  Upon completion of the study another share payment was due.
That press release was interesting. I personally had never seen one like this before.
Some may see independence as an issue with their fiscal arrangement. Maybe… but this blog isn’t about the need for independent QP’s.  In fact I don’t recall feasibility studies having that requirement.  Some 43-101 resources estimates do require independence.
An industry discussion about where independence is required would be an interesting exercise.  However I will leave that conversation for a future post.

Would you work for company shares only?

I have never been in a situation where I was consulting with  company shares as my compensation.  Neither have I ever managed a study where outside consultants were being paid in shares.   However I can see the possibility of interesting dynamics at play.
In the past I have worked as an owner’s study manager and been awarded stock options along with salary.  In that role, my job was to look after the owner’s interests, pushing for cost efficiencies and optimizations.
Regarding share compensation, there are significant risks on the consultant’s side when they agree to be paid in shares.   I can see both positive and negative aspects with that type of a relationship.
I am not passing judgement here on what is right or wrong.  My objective is to comment on some basic issues that may arise.

Pro’s and Con’s

The positive aspects one might experience include;
  • It’s easier for the company to pay for the study since there are no cash outlays from the treasury.
  • The consultants might have the company’s best interests at heart since they will now be part owners of the company.
  • Possibly there will be greater technical effort to produce optimal designs and cost estimating efficiencies in the drive for great economics.
The potential pitfalls of this approach might include;
  • A public perception that the study is not impartial.
  • There is an overhang of shares that may be dumped onto the market in the near future.
  • Possibly the consultant will charge a premium for their services due to the financial risks they are taking.
  • The company may be more tolerable of study cost overruns since there is no hard cash outlay.
Regarding the first item “impartiality”, in the past there have been questions raised about the impartiality of engineering firms. I first recall reading this claim many years ago in a public response to a mining EIA application. Unfortunately I cannot find the exact source now.
The concern was whether the consultant’s work would be overly optimistic, seeing that they would eventually gain as a project moved from PEA through to the PFS and FS stages. They didn’t want to kill the golden goose. The project’s opponents were making the argument to the regulators “don’t believe what the engineering company is telling you”.
I’m curious how many times this argument has been used, seeing that it’s been around for some time.

Conclusion

It would be interesting to know how many consulting firms would be willing to accept compensation solely in shares.  Stock prices move up and down and the outcome of the study itself can have an impact on  share performance.
Unlike being paid in bitcoin, which also fluctuates in value, shares will generally have a hold period before they can be sold off.  This further increases the consultant’s risk.
I am curious to see whether the First Mining + Ausenco financial arrangement will create a precedent. Possibly it happens more than I am aware of.  Realistically I don’t see anything wrong with the approach, although one needs to understand the perceptions that it can create.   See where you sit if you were on the owner’s or consultant’s side and this idea was being discussed.  What would you do?
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43-101 Reports – What Sections Are Missing?

Recently as part of a due diligence I was reviewing a couple of 43-101 technical reports and something jumped out at me. There were pages and pages of statistical plots. The plots included QA/QC and check assay diagrams, variograms, box plots, swath plots, and contact plots. There was no lack of statistical information. However, as a mining engineer, there was something missing that was of interest to me. Good geological sections were missing.
Its seems that most technical reports focus heavily on describing the mathematical aspects of the resource, but spend less time describing the physical aspects of the geology and the mineability.

Who is the audience

It’s always open to debate who these 43-101 technical reports are intended for. Generally we can assume correctly that they are not being written mainly for geologists. However if they are intended for a wider audience of future investors, shareholders, engineers, and C-suite management, then (in my view) greater focus needs to be put on the physical orebody description.
Understanding the nature of the orebody brings greater understanding of the entire project.

Everyone likes geology

Whenever I listen to investor conference calls, many of the analyst’s questions relate to the resource and the mining operation. Essentially the participants want to know if this will be an “easy” mine or a “hard” mine.
One simple way to explain this is with good geological sections. They help everyone understand any potential issues; i.e. a picture is worth a thousand words. Good cross-sections will describe the following aspects.
  • The complexity (or simplicity) of the ore zones,
  • The width of the ore zones,
  • The vertical extent of geological information,
  • The drill spacing and drilling density,
  • The spatial distribution of assay information,
  • The grade distribution laterally and vertically,
  • The waste distribution throughout the mine,
  • The mining block size in relation of the ore zone dimensions
One can learn a lot just by looking at well presented cross-sections.  The nice thing is that they are generally understood by non-technical people.

Suggestions

I would like to suggest that every technical report includes more focus on the operational aspects of the orebody.
My recommendation is that the following information becomes standard in all technical reports.
  1. At least three to five cross sections through the deposit. Don’t just present a best case typical cross-section.
  2. At least one or two longitudinal sections.
  3. At least three level or bench plans, showing the drill hole pierce points.
Each cross section/bench plan should consist of two parts.
Part 1 shows the drill holes with color coded grade intercepts, ore zone wireframes, and lithology or rock types.
Part 2 should be a block model cross section showing the wireframes, drill holes, and color coded block model grades using the ore/waste cutoff grade as one of the clearly defined grade bins.
It doesn’t really matter if the cross- sections are included in Section 14 or Section 16 of the Technical Report. However if they are included in Section 16 then one should overlay the pit design and/or underground stope shapes onto the sections.
I also recommend NOT incorporating these cross-sections in the appendices since they are too important to be hidden away. They should be described in the main report itself.

Conclusion

Improving the quality of information presented to investors is one key way of maintaining trust with investors. Accordingly we should look to improve the description of the mineable ore body for everyone. In many cases it is the key to the entire project.
I am not suggesting that one needs to remove the statistical plots since they do have their purpose and audience. I am simply suggesting that we should not forget about everyone else try to figured out the viability of the project.
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43-101 and the Shrinking Feasibility Study

There is current sense that advanced mining studies are suffering from a lack of credibility with investors. Curiously it seems to me that many feasibility study documents are getting smaller at the same time. Might there be some link between the two?
My personal exposure to feasibility studies extends from managing them, participating in them, and undertaking due diligence reviews of them. Earlier in my career mining feasibility studies typically consisted of comprehensive documents, often contained in several binders of information. The study could generate a lot of paper. However currently it seems that often (not always) the 43-101 Technical Report can be the “final” feasibility study document.
In the past there would be binders with detailed calculations and backup for the different parts of the study. Typically there was a binder for the Executive Summary and separate sections (i.e. binders) for Geology, Mining, Processing, Infrastructure, Capital Cost, Operating Cost, Environmental, Project Execution, and Economic Analysis, etc.
The comprehensive report normally had both the report text and the details of the work done. This might include hand sketches, haul cycles, vendor price quotes, spec sheets, email correspondences, the WBS cost estimate detail, and so on.
The section appendices also included 3rd party reports like pit slope geotechnical studies, hydrogeological analysis, tailings dam designs, etc. The feasibility document might have included CD’s with the entire study in electronic format.
Generally all the supporting information for the study was in that comprehensive document. They were great. You knew you were somebody if you were given a personal copy of the entire report for your office.

43-101 Technical Report

The original intent of the 43-101 Technical Report was for it to be a summary document, only about 80-150 pages in length. The intent was to simplify all the technical work for the benefit of non-technical investors. Currently I have noticed that in many cases the 43-101 report is now the entire feasibility study document.
These 43-101 reports contain a fair amount of detail and they can exceed 400 pages in length. I’m not sure how many non-technical people actually read them beyond the Executive Summary or even read them at all.
Unfortunately if one is undertaking a due diligence review of a project, the 400 page Technical Report won’t contain the detail needed for a proper technical review. When more detail is requested, we are usually provided with a series of production and cost spreadsheets that need to be deciphered.  Furthermore the spreadsheets themselves don’t give the sources or basis for all the input data.
In my view the 400 page Technical Report is too confusing for the investing public and not detailed enough for technical review, thereby really satisfying no one.
Why aren’t the comprehensive feasibility study documents being completed all the time? I would suggest it is because of the effort and cost. It takes time to properly document all aspects of a study, creating legible tables, scanning files, and merging it all into a single PDF document. Preparing a 43-101 Technical Report can be a chore, as many of us have experienced in trying to meet the 45 day deadline. So who wants to take on the task of preparing an even larger document?

Recommendation

My recommendation is that, where budgets permit, mining companies return to the days of preparing the comprehensive feasibility study document. It’s the right thing to do.
One doesn’t need to print the entire report on paper since PDF files will work fine. Scanning of some sketches, vendor quotes may add an extra step, but that is hardly a momentous chore. Most 3rd party documents are already been submitted in PDF format so coordinating and merging will be the main task.
The 43-101 Technical Report could return to being a more investor friendly summary style document rater than a full study report.
This comprehensive document approach would apply to both pre-feasibility and feasibility studies that are used for advanced financing purposes.  The re-adoption of the comprehensive report format should be consistent among both large miners and juniors.

What about the PEA

The preliminary economic assessment (PEA) likely does not warrant a comprehensive report. The PEA is not definitive. I have also heard that the PEA is losing some credibility with investors, with some people referring to it as mainly a sales document. I don’t necessarily agree with that sentiment, but I understand why some see it that way.
As an aside, an interesting panel discussion might be whether the PEA has actually lost credibility, and if so, how can we restore credibility. My thoughts on PEA’s were summarized in a previous blog “Not All PEA’s Are Created Equal”.

Conclusion

If any mining industry credibility has been lost, re-establishing it should be important. One way to start doing this is to focus on creating the type of reports that best serve the needs of the industry stakeholders.
Some may say returning to comprehensive reports are a step backwards while mining needs to move forward. In my opinion, moving forward is going from less documented studies towards well documented studies.
One of the most technically detailed feasibility studies that I worked on was for the Diavik diamond project. This was a one-of-a-kind project operated by a well run risk-averse company (Rio Tinto). Every aspect of the project was documented to the upmost extent, although the company had the deep pockets to do that.  Funny thing though, as part of the internal Rio Tinto engineering team I don’t recall ever producing a final report document there (perhaps my recollections have been blurred since 20 years ago).
Once you have established the type of report you want, make sure your consultants clearly understand the expected deliverable. I recommend that someone on your team prepares an RFP document to lay out your wish list, even if sole sourcing the study. A previous blog was written on this topic at Request For Proposal (“RFP”) – Always Prepare One
As an aside, it would be interesting to know if those undertaking due diligence’s in the UK or Australia (i.e. not under 43-101 domain) have seen any changes in the quality of feasibility study documentation.
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Ore Dilution – An Underground Perspective

A few months ago I wrote a blog about different approaches that mining engineers are using to predict dilution in an open pit setting. You can read the blog at this link. Since that time I have been in touch with the author of a technical paper on dilution specifically related to underground operations. Given that my previous blog was from an open pit perspective, an underground discussion might be of interest and educational.
The underground paper is titled “Mining Dilution and Mineral Losses – An Underground Operator’s Perspective” by Paul Tim Whillans. You can download the paper at this link.

Here is the abstract

For the underground operator, dilution is often synonymous with over-break, which mining operations struggle to control. However, there are many additional factors impacting dilution which may surpass the importance of overbreak, and these also need to be considered when assessing a project. Among these, ore contour variability is an important component of both dilution and mineral losses which is often overlooked.  Mineral losses are often considered to be less important because it is considered that they will only have a small impact on net present value. This is not necessarily the case and in fact mineral losses may be much higher than indicated in mining studies due to aggregate factors and may have an important impact on shorter term economics.

My key takeaways

I am not going into detail on Paul’s paper, however some of my key takeaways are as follows. Download the paper to read the rationale behind these ideas.
  • Over-break is a component of dilution but may not be the major cause of it. Other aspects are in play.
  • While dilution may be calculated on a volumetric basis, the application of correct ore and waste densities is important. This applies less to gold deposits than base metal deposits, where ore and waste density differences can be greater.
  • Benchmarking dilution at your mine site with published data may not be useful. Nobody likes to report excessively high dilution for various reasons, hence the published dilution numbers may not be entirely truthful.
  • Ore loss factors are important but can be difficult to estimate. In open pit mining, ore losses are not typically given much consideration. However in underground mining they can have a great impact on the project life and economics.
  • Mining method sketches can play a key role in understanding underground dilution and ore losses, even in today’s software driven mining world.
  • Its possible that many mine operators are using cut-off grades that are too low in some situations.
  • High grading, an unacceptable practice in the past, is now viewed differently due to its positive impact on NPV. (Its seems Mark Bristow at Barrick may be putting a stop to this approach).
  • Inferred resources used in a PEA can often decrease significantly when upgraded to the measured and indicated classifications. If there is a likelihood of this happening, it should be factored into the PEA production tonnage.
  • CIM Best Practice Guidelines do not require underground ore exposure for feasibility studies. However exposing the ore faces can have a significant impact on one’s understanding of the variability of the ore contacts and the properties of minor faults.

Conclusion

The bottom line is that not everyone will necessarily agree with all the conclusions of Paul’s paper on underground dilution. However it does raise many issues for technical consideration on your project.
All of us in the industry want to avoid some of the well publicized disappointments seen on recent underground projects. Several have experienced difficulty in delivering the ore tonnes and grades that were predicted in the feasibility studies. No doubt it can be an anxious time for management when commissioning a new underground mine.
Note: previously I had shared another one of Paul’s technical papers in a blog called “Underground Feasibility Forecasts vs Actuals”. It also provides some interesting insights about underground mining projects.
If you need more information, Paul Whillans website is at http://www.whillansminestudies.com/.
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Mining Due Diligence Checklist

It doesn’t matter how long you have worked in the mining industry, at some point you will probably have taken part in a due diligence review. You might have been asked to help create a data room. Perhaps your company is looking at a potential acquisition. Maybe you’re a consultant with a particular expertise needed by a due diligence team. It’s likely that due diligence has impacted on many of us at some point in our careers.
The scope of a due diligence can be exceptionally wide. There are legal, marketing, and environmental aspects as well as all the technical details associated with a mining project. The amount of information provided can be overwhelming sometimes.

I’m a big fan of checklists

Checklists are great and they can be very helpful in a due diligence review. A scope checklist is a great way to make sure things don’t fall through the cracks. A checklist helps keep a team on the same page and clarifies individual roles and tasks. Checklists bring focus and minimize sidetracking down unnecessary paths.
Recognizing this, I have created a personal due diligence checklist for such times. A screen shot of it is shown below. The list is mainly tailored for an undeveloped project but it still has over 230 items that might need to be considered.

Each due diligence is unique

Not all of the items in the checklist are required for each review. Maybe you’re only doing a high level study to gauge management’s interest in a project. Maybe you’re undertaking a detailed review for an actual acquisition or financing event. It’s up to you to create your own checklist and highlight which items need to be covered off. The more items added the less risk in the end; however that requires a longer review period and greater cost.
You a create your own checklist but if you would like a copy of mine just email me at KJKLTD@rogers.com and let me know a bit about how you plan to use it (for my own curiosity). Specify if you would prefer the Excel or PDF versions.
Please let me know if you see any items missing or if you have any comments.
Now that we have an idea of what information we need to examine in a due diligence, the next question is where to find it.
Previously I had written a blog titled “Due Diligence Data Rooms – Help!” which discussed how we can be overwhelmed by a poorly set up data room. My request is that when setting up a data room, please consider the people who will be accessing it.

Due Diligence isn’t for everyone

Due diligence exercises can be interesting and great learning experiences, even for senior people that have seen it all. However they can also be mentally taxing due to the volumes of information that one must find, review, and understand all in a short period of time.
Some people are better at due diligence than others. It helps if one has the ability to quickly develop an understanding of a project. It also helps to know what key things to look for, since many risks are common among projects.
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Ore Dilution Prediction – Its Always an Issue

mining reserve estimation
Over my years of preparing and reviewing mining studies, ore dilution often seems to be a contentious issue.  It is deemed either too low or too high, too optimistic or too pessimistic.  Everyone realizes that project studies can see significant economic impacts depending on what dilution factor is applied.  Hence we need to take the time to think about what dilution is being used and why.

Everyone has a preferred dilution method.

I have seen several different approaches for modelling and applying dilution.   Typically engineers and geologists seem to have their own personal favorites and tend to stick with them.   Here are some common dilution approaches.
1. Pick a Number:
This approach is quite simple.  Just pick a number that sounds appropriate for the orebody and the mining method.  There might not be any solid technical basis for the dilution value, but as long as it seems reasonable, it might go unchallenged.
2. SMU Compositing:
This approach takes each percent block (e.g.  a block is 20% waste and 80% ore) and mathematically composites it into a single Selective Mining Unit (“SMU”) block with an overall weighted average grade.  The SMU compositing process will incorporate some waste dilution into the block.  Possibly that could convert some ore blocks to waste once a cutoff grade is applied.   Some engineers may apply additional dilution beyond SMU compositing while others will consider the blocks fully diluted at the end of this step.
3. Diluting Envelope:
This approach assumes that a waste envelope surrounds the ore zone.  One estimates the volume of this waste envelope on different benches, assuming that it is mined with the ore.  The width of the waste envelope may be correlated to the blast hole spacing being used to define the ore and waste mining contacts.  The diluting grade within the waste envelope can be estimated or one may simply assume a more conservative zero-diluting grade.   In this approach, the average dilution factor can be applied to the final production schedule to arrive at the diluted tonnages and grades.  Alternatively, the individual diluted bench tonnes can be used for scheduling purposes.
4. Diluted Block Model:
This dilution approach uses complex logic to look at individual blocks in the block model, determine how many waste contact sides each block has, and then mathematically applies dilution based on the number of contacts.  Usually this approach relies on a direct swap of ore with waste.  If a block gains 100 m3 of waste, it must then lose 100 m3 of ore to maintain the volume balance.   The production schedule derived from the “diluted” block model usually requires no subsequent dilution factor.
5. Using UG Stope Modelling
I have also heard about, but not yet used, a method of applying open pit dilution by adapting an underground stope
modelling tool.  By considering an SMU as a stope, automatic stope shape creators such as Datamine’s
Mineable Shape Optimiser (MSO) can be used to create wireframes for each mining unit over the entire
deposit. Using these wireframes, the model can be sub-blocked and assigned as either ‘ore’ (inside the
wireframe) or ‘waste’ (outside the wireframe) prior to optimization.   It is not entirely clear to me if this approach creates a diluted block model or generates a dilution factor to be applied afterwards.

 

When is the Cutoff Grade Applied?

Depending on which dilution approach is used, the cutoff grade will be applied either before or after dilution.   When dilution is being added to the final production schedule, then the cutoff grade will have been applied to the undiluted material (#1 and #2).
When dilution is incorporated into the block model itself (#3 and #4), then the cutoff grade is likely applied to the diluted blocks.   The timing of when to apply the cutoff grade will have an impact on the ore tonnes and had grade being reported.

Does one apply dilution in pit optimization?

Another occasion when dilution may be used is during pit optimization.  There are normally input fields for both a dilution factor and an ore loss factor.   Some engineers will apply dilution at this step while others will leave the factors at zero.  There are valid reasons for either approach.
My preference is use a zero dilution factor for optimization since the nature of the ore zones will be different at different revenue factors and hence dilution would be unique to each.   It would be good to verify the impact that the dilution factor has on your own pit optimization, otherwise it is simply being viewed as a contingency factor.

Conclusion

My personal experience is that, from a third party review perspective, reviewers tend to focus on the final dilution number used and whether it makes sense to them.   The actual approach used to arrive at that number tends to get less focus.
Regardless of which approach is being used, ensure that you can ultimately determine and quantify the percent dilution being applied.  This can be a bit more difficult with the mathematical block approaches.
Readers may yet have different dilution methods in their toolbox and I it would be interesting to share them.
Note: If you would like to get notified when new blogs are posted, then sign up on the KJK mailing list on the website.  Otherwise I post notices on LinkedIn, so follow me at: https://www.linkedin.com/in/kenkuchling/.
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Mining Press Releases – Where to Get Them

mining news
There are a lot of sources of mining information on the internet.  These encompass topics such as technical articles, analyst opinions, and company press releases. If your interest is largely company news releases, what is the best way to get these?
One way is to go to the individual company website and sign-up one their mailing list. This approach generally works well but it forces you to sign up on a myriad of websites if you intend to follow a lot of companies.

There are alternatives

One option is to sign-up for a free account with a newswire service where you can select specific companies to follow.  You will get emailed news releases as soon as they are disseminated. The nice thing here is that you can select mining companies, non-mining public companies, as well as entire industries. Here are some that I personally use.
Marketwire: There you can create a “Hot Off the Wire” account and then select your companies of interest. You can also select entire industries to add to your company list.
CNW Group Ltd.  Create an account at Cision and search various companies to add to your “My Subscriptions” list.Junior Mining News screenshot
Junior Mining News is another source to get general news updates via their daily newsletter (see screenshot). Their daily email gives a brief summary of today’s news events and includes “Read More..” links if you want the entire press release. This website accesses some of the same news release distributors as mentioned above so there could be some repetition from time to time.

Its easy

Using the services described above, it’s easy to sign up for multiple companies, too many companies in fact. Its easy to get inundated with emails.
Public companies need to keep an active news flow  and some companies are very good at it.
By using the press release distribution websites you are consolidating your requests, thereby making it easier to control the amount of information you want to receive.
Feel free to share your method for tracking companies, whether using some of the same services or something entirely different.
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Disrupt Mining Challenge – Watch for it at PDAC

Update:  This blog was originally written in January 2016, and has been updated for Jan 2018.

Gold Rush Challenge

In 2016 at PDAC, Integra Gold held the first the Gold Rush Challenge.  It was an innovative event for the mining industry.  It was following along on the footsteps of the Goldcorp Challenge held way back in 2001.
The Integra Gold Rush Challenge was a contest whereby entrants were given access to a geological database and asked to prepare submissions presenting the best prospects for the next gold discovery on the Lamaque property.  Winners would get a share of the C$1 million prize.
Integra Gold hoped that the contest would expand their access to quality people outside their company enabling their own in-house geological team to focus on other exploration projects.   In total 1,342 entrants from over 83 countries registered to compete in the challenge.  A team from SGS Canada won the prize.

Then Disrupt Mining came along

In 2017, its seem the next step in the innovation process was the creation of Disrupt Mining sponsoerd by Goldcorp.  Companies and teams developing new technologies would compete to win a $1 million prize.
In 2017, the co-winning teams were from Cementation Canada (new hoisting technology) and Kore Geosystems (data analystics for decision making).
In 2018, the winning team was from Acoustic Zoom, an new way to undertake seismic surveys.

The 2019 winners will be announced at PDAC.  The entry deadline has passed so you’re out of luck for this year.

Conclusion

At PDAC there are always a lot of things to do, from networking, visiting booths, presentations, trade shows, gala dinners, and hospitality suites.
Now Disrupt Mining brings another event for your PDAC agenda.
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Measured vs. Indicated Resources – Do We Treat Them the Same?

measured and indicated
One of the first things we normally look at when examining a resource estimate is how much of the resource is classified as Measured or Indicated (“M+I”) compared to the Inferred tonnage.  It is important to understand the uncertainty in the estimate and how much the Inferred proportion contributes.   Having said that, I think we tend to focus less on the split between the Measured and Indicated tonnages.

Inferred resources have a role

We are all aware of the regulatory limitations imposed by Inferred resources in mining studies.  They are speculative in nature and hence cannot be used in the economic models for pre-feasibility and feasibility studies. However Inferred resource can be used for production planing in a Preliminary Economic Assessment (“PEA”).
Inferred resources are so speculative that one cannot legally add them to the Measure and Indicated tonnages in a resource statement (although that is what everyone does).   I don’t really understand the concern with a mineral resource statement if it includes a row that adds M+I tonnage with Inferred tonnes, as long as everything is transparent.
When a PEA mining schedule is developed, the three resource classifications can be combined into a single tonnage value.  However in the resource statement the M+I+I cannot be totaled.  A bit contradictory.

Are Measured resources important?

It appears to me that companies are more interested in what resource tonnage meets the M+I threshold but are not as concerned about the tonnage split between Measured and Indicated.  It seems that M+I are largely being viewed the same.  Since both Measured and Indicated resources can be used in a feasibility economic analysis, does it matter if the tonnage is 100% Measured (Proven) or 100% Indicated (Probable)?
The NI 43-101 and CIM guidelines provide definitions for Measured and Indicated resources but do not specify any different treatment like they do for the Inferred resources.
CIM Resources to Mineral Reserves

Relationship between Mineral Reserves and Mineral Resources (CIM Definition Standards).

Payback Period and Measured Resource

In my past experience with feasibility studies, some people applied a  rule-of-thumb that the majority of the tonnage mined during the payback period must consist of Measure resource (i.e. Proven reserve).
The goal was to reduce project risk by ensuring the production tonnage providing the capital recovery is based on the resource with the highest certainty.
Generally I do not see this requirement used often, although I am not aware of what everyone is doing in every study.   I realize there is a cost, and possibly a significant cost, to convert Indicated resource to Measured so there may be some hesitation in this approach. Hence it seems to be simpler for everyone to view the Measured and Indicated tonnages the same way.

Conclusion

NI 43-101 specifies how the Inferred resource can and cannot be utilized.  Is it a matter of time before the regulators start specifying how Measured and Indicated resources must be used?  There is some potential merit to this idea, however adding more regulation (and cost) to an already burdened industry would not be helpful.
Perhaps in the interest of transparency, feasibility studies should add two new rows to the bottom of the production schedule. These rows would show how the annual processing tonnages are split between Proven and Probable reserves. This enables one to can get a sense of the resource risk in the early years of the project.  Given the mining software available today, it isn’t hard to provide this additional detail.
Note: If you would like to get notified when new blogs are posted, then sign up on the KJK mailing list on the website.  Otherwise I post notices on LinkedIn, so follow me at: https://www.linkedin.com/in/kenkuchling/.
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