Articles tagged with: PEA

Measured vs. Indicated Resources – Do We Treat Them the Same?

Date: January 19, 2016 Author: Ken Kuchling Comments: 6 Replies
measured and indicated
(Orig 2016  Updated 2026) One of the first things we normally look at when examining a mineral resource estimate is how much of the resource is classified as Measured and Indicated (“M+I”) and then compare that to the Inferred tonnage.  It seems to be important to understand the uncertainty in the resource estimate and how much the Inferred contributes to the overall tonnage.  Sometimes we even break the rules and add together the M+I tonnage with the Inferred tonnage.
The mining engineer needs to juggle all three classifications.  Having said that, how much emphasis do we put on the split between the Measured and Indicated tonnages?   How much emphasis should be put on the Inferred resource by itself?

Inferred Resources Play a Role

We are all aware of the NI 43-101 restrictions imposed on the Inferred resources in mining studies.  They are deemed highly speculative, and hence cannot be used in the economic models for pre-feasibility and feasibility studies. However Inferred resource are used for pit design and production planing in a Preliminary Economic Assessment (“PEA”).
Inferred resources are so speculative that a company is not permitted to add them to the Measure and Indicated tonnages in a resource statement (although that is what every investor automatically does).   I don’t really understand that concern in a Mineral Resource statement if it clearly includes a line that adds M+I tonnage with Inferred tonnes – as long as everything is transparent.  It provides an easy way to see what portion of the total resource is Inferred.
Its a bit contradictory that when a PEA mining schedule is developed, the three resource classifications can be combined into a single tonnage value.  However in the Mineral Resource statement itself, the M+I+I cannot be totaled.
I understand that a company must provide information as to how much of the PEA production schedule is based on Inferred Resources, although often they do not provide this breakdown.  Next time you are reviewing a 43-101 report for a PEA, take a look if it is provided.

Are Measured Resources Important?

It appears to me that investors are often more interested in what resource tonnage meets the M+I threshold but are less focussed on the tonnage split between Measured and Indicated.
It seems that M+I are largely viewed as being somewhat the same.  Since both Measured and Indicated resources can be used in a pre-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 Mineral Resources, but do not specify any different treatment like they do for the Inferred resources.   If Measured has more certainty than Indicated, should we be able to apply their tonnages interchangeably?
CIM Resources to Mineral Reserves

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

In my experience with some feasibility studies, a few people did apply a  rule-of-thumb that the majority of the tonnage mined during the payback period must consist of higher confidence Measure resource (i.e. Proven reserve).
The idea was to reduce project risk by ensuring the production tonnage during the capital recovery period is mining the resource with the highest certainty in tonnes and grade.
Generally I do not see this requirement used that often anymore, although I am not aware of what everyone is doing in every study.  It would be good to see more  transparency on this in the studies.  Perhaps this may explain why some recent projects put into production had difficulty meeting grade targets and then ran into trouble.
I realize there is a cost, and possibly a significant cost, to infill drill to convert Indicated resource to Measured.  Hence there may be some hesitation in this approach. Likely it is simpler for everyone to just view the Measured and Indicated tonnages as one.  Note that some algorithyms are now available to help optimize infill drill programs to get the most bang for the buck (see this blog pot Let A.I. Help Target Your Infill Drilling).

Conclusion

NI 43-101 specifies how the Inferred resource can and cannot be used.  Given some of the project failures, is it a matter of time before the regulators start specifying how Measured and Indicated resources must be used?  There is  merit to this idea, however adding more regulation (and cost) to an already burdened industry would not be helpful. Ultimately it is up to the mining companies and financiers as to how far they want to see the re-risking step go.
In lieu of more regulations, 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 mining and processing tonnages are split between Proven (Measured) and Probable (Indicated) categories. This would enable one to can get a sense of the resource risk in the early years of the project.
Given the capabilities of today’s mining software, it is not difficult to provide this additional detail.   Companies with a high proportion of Measured in their Feasibility Study can use this a way to promote their de-risking efforts.   Now we just need to ensure that the resource estimation consultants actually classify Measured as very high certainty resources.
I don’t want to give the impression that Inferred resources are unimportant.  They do play a role in mine design and permitting, as discussed in this post “The Double Life of Inferred Resources: Now You See It – Now You Don’t“.

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For some free mining calculator apps, including project timelines and a simplified cashflow modeller, check out this website https://sites.google.com/view/drillingdown
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Mining Cashflow Sensitivity Analyses – Be Careful

Date: June 15, 2015 Author: Ken Kuchling Comments: 1 Reply
cashflow sensitivity
One of the requirements of NI 43-101 for Item 22 Economic Analysis is “sensitivity or other analysis using variants in commodity price, grade, capital and operating costs, or other significant parameters, as appropriate, and discuss the impact of the results.”
The typical result of this 43-101 requirement is the graph seen below (“a spider graph”, which is easily generated from a cashflow model.  Simply change a few numbers in the Excel file and then you get the new economics.  The standard conclusions derived from this chart are that metal price has the greatest impact on project economics followed by the operating cost.   Those are probably accurate conclusions, but is the chart is not telling the true story.
DCF Sensitivity GraphI have created this same spider graph in multiple economic studies so I understand the limitations with it.   The main assumption is that all of the sensitivity economics are based on the exact same mineral reserve and production schedule.
That assumption may be applicable when applying a variable capital cost but is not applicable when applying varying metal prices and operating costs.
Does anyone really think that, in the example shown, the NPV is $120M with a 20% decrease in metal price or 20% increase in operating cost?   This project is still economic with a positive NPV.
In my view, a project could potentially be uneconomic with such a significant decrease in metal price but that is not reflected by the sensitivity analysis.  Reducing the metal price would result in a change to the cutoff grade.  This changes the waste-to-ore ratio within the same pit.  So assuming the same size mineral reserve is not correct in this scenario.
Changes in economic parameters would impact the original pit optimization used to define the pit upon which everything is based.
A smaller pit size results in a smaller ore tonnage, which may justify a smaller fleet and smaller processing plant, which would have higher operating costs and lower capital costs.
A smaller mineral reserve would produce a different production schedule and shorter mine life.  It can  get quite complex to examine it properly.
Hence the shortcut is to simply change inputs to the cashflow model and generate outputs that are questionable but meet the 43-101 requirements.
The sensitivity information is not just nice to have.   Every mining project has some flaws, which can be major or minor. Management understandably have a difficult task in making go/no-go decisions. Financial institutions have similar dilemmas when deciding on whether or not to finance a project.   You can read that blog post at this link “Flawed Mining Projects – No Such Thing as Perfection“
So if the spider chart isnt he best way to tackle the risk issue, what way is better?  In another blog post I discuss an different approach using the probabilistic risk evaluation (Monte Carlo).  Its isn’t new but now well adopted yet by the mining industry.  You can learn more at “Mining Financial Modeling – Make it Better!“
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Request For Proposal (“RFP”) – Always Prepare One

Date: May 15, 2015 Author: Ken Kuchling Comments: Leave a reply
Mining request for proposal
When it comes to time to undertake any type of mining study, whether small or large, whether sole sourced or competitively bid, it is always a good idea to prepare a Request For Proposal (“RFP”) document.
I know that it can be an annoyance, but an RFP document is a lot better than a simply phone calling a consultant describing what you want.  Its also better than a cursory email outlining what you want. In many cases the RFP doesn’t need to be a complex document; however RFP’s are appreciated by everyone involved.   It provides the documentation that can help make things go smoothly.

The RFP doesn’t need to be complicated

executive meetingOwner’s Perspective: preparing an RFP gives the opportunity to collect the Owner’s team thoughts on the scope of study needed, on the deliverables required, and on the timing.   The RFP will outline this for the consultants and simultaneously help the owner’s team to get on the same page themselves.
The RFP is the opportunity for the owner to tell the consultants exactly what they are looking for in the mining study.  It also specifies what they want to see in the proposal to help them compare multiple proposals if needed.
Consultant’s perspective: receiving an RFP is great to them since having a detailed scope of work laid out means they don’t need to guess the scope when preparing their cost estimate.  It will be clear to the consultant what work is “in scope”.  If extra services are required in the future, then “out-of-scope” work can be defended.
An RFP also gives the consultant some reassurance that the Owner has put thought into exactly what they want them to do.

What to include in the RFP

The RFP sent to bidding consultants should contain (at a minimum) the items listed below. A sole sourced study can have a scaled back RFP document, but many of these key items should be maintained.
Much of this RFP information can be a single template document that will be modified if different scopes of work will be sent to different consultants (e.g. tailings design, pit geotechnical, groundwater, feasibility study, etc.).
  • Project Introduction (a high level overview of the project and the Owner).
  • Table of Responsibilities for the Study (if other consultants are being involved in different areas).
  • Scope of Work (for this Proposal), and highlight any specific exclusions from the scope.
  • Additional Requirements (update meetings, monthly reports, timesheets, documentation, etc.)
  • Schedule (the timing for the proposal, job award date, study kickoff, and completion date).
  • Instructions to the Bidder (e.g. what information should be provided in each proposal and in what format).
  • Other (the legal rights of the Owner, confidentiality statement, how proposals will be evaluated, etc.).

Specifying format makes it easier to compare proposals

If a company is competitively bidding the study, it can be easier to compare multiple proposals if certain parts are presented in the exact same format.  Usually different consulting firms have their own proposal format, which is fine, however certain sections of the proposal should be made easily comparable.
The RFP can request that each proposal should contain (at a minimum):
  • Confirmation of the scope of work based on the RFP, which may be more detailed than the RFP itself.
  • List of exclusions.
  • List of final deliverables.
  • Proposed Study Manager, resume and relevant study management experience.
  • Proposed team members, organizational structure by areas of responsibility, and resumes.
  • Cost estimate on a not-to-exceed basis for each area, subdivided by team member, hours and unit rates ,and possibly in a specific table format.
  • A fee table for the various job classifications that would be applied to out-of-scope additional man hours.
  • All indirect costs, administrative costs, indicating mark-ups (if any).
  • Miscellaneous disbursements (i.e., airfares, hotel, vehicles) and indicate if there are mark-ups.
  • Detailed study schedule to completion.
  • Payment schedule.
  • Specify if there are any potential conflicts of interest with other projects.

Conclusion

The bottom line is that an owner should always take the time to prepare some type of RFP for any mining study they want to undertake.  The owner should also request a consultant proposal based on that RFP, even if it is being sole sourced to just one consultant.
Depending on the size and nature of the study, one can use judgement on how detailed the RFP or consultant’s proposal must be, but one should always have the proper documentation in place beforehand.
A key part of any mining study is the project capital cost estimate.  In my view it is important that any RFP includes the requirement to develop a Work Breakdown Structure.  This has many uses, and is discussed further in the blog post “Work Breakdown Structures – Don’t Forget About The WBS“
My entire blog post library can be found at this LINK with topics ranging from geotechnical, financial modelling, and junior mining investing.

 

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Google Earth – Keep it On Hand

Date: May 8, 2015 Author: Ken Kuchling Comments: 1 Reply
Mining studies
In a previous blog post “Mine Site Visit – What Is the Purpose?” I briefly discussed the requirements for a mine site visit to be completed by one or more Qualified Persons (“QP”) in a 43-101 compliant study.    Unfortunately normally the entire study team cannot participate in a site visit; however the next best thing may be Google Earth.

See the Mine Site with Google Earth

Gather your team around their computers and fire up screen sharing software like Teams, GoToMeeting, Skype, or Zoom.  Give control of the mouse to someone who knows the site well.  Here are some of the things you can do on your group tour.
  • You can fly-around the project site examining the topography.
  • You can view regional features, regional facilities, land access routes, and existing infrastructure.
  • You can measure distances (or areas), either in a straight line or along a zigzag path.
  • You can view historical aerial photos (if they exist) to show how the area may have changed over time.
  • You can import GPS tracks and survey waypoints.  If a member of the study team has visited the site with a GPS, they can illustrate their route and their observations.
My recommendation, at the start of a study, is to always have a Google Earth session with your technical team to examine the project site and the regional infrastructure.
A group session like this ensures that everyone sees and hears the same thing. It’s like taking a helicopter tour of the site with your entire study team at once.   A “helicopter tour” would be a good agenda item at the very first kickoff meeting.
Another option is to check the aerial photos and Bird’s Eye views on the Bing Maps website (www.bing.com/maps).  Sometimes those images will be different than what you will find in Google Maps or Google Earth.
As mentioned above, for those still interested the  previous blog post is at “Mine Site Visit – What Is the Purpose?“
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Large or Small Mining Consulting Firms – Any Difference?

Date: May 7, 2015 Author: Ken Kuchling Comments: 2 Replies
Mining feasibility pre-feasibility
Some junior mining companies select their mining study consultant based on the assumption that they need a “big name” firm to give credibility to their study.   This creates an interesting dilemma for many smaller mining companies since they the larger firms can cost more.  Its also a dilemma for smaller engineering firms trying to win jobs.  While large consultants may cost more due to higher overheads; their brand name on a study may bring some value.
In my personal experience I find that larger consultants are best suited for managing the large scale feasibility studies.  This isn’t because they necessarily provide better technical expertise.  Its because they generally have the internal project management and costing systems to manage the complexities of such larger studies.
The larger firms are normally able to draw in more management resources; for example, project schedulers, cost estimators, and document control personnel.  Ultimately one will pay for all of these people, albeit they may be a critical part in successfully completing the study.
A feasibility study is more rigorous than a pre-feasibility study, which in turn is more rigorous than a PEA or scoping study.

Sub-contracting Parts

For certain aspects of a feasibility study, one may get better technical expertise by subcontracting to smaller highly specialized engineering firms.  However too much subcontracting may become an onerous task.  Often the larger firms may be better positioned to do this.
In my view, likely the best result will come from a combination of a large firm managing the feasibility study but undertaking only the technical aspects for which they are deemed to be experts.
The large lead firm would be supported by smaller firms for the specialized aspects, as per a previous article “Multi-Company Engineering Studies Can Work Well..Or Not”.

What about smaller studies?

For smaller studies, like scoping studies (i.e. PEA’s), which can be based on limited amounts of technical data, I  don’t see the need to award these studies to large engineering firms.  The credibility of such early studies will be linked to the amount of data used to support the study.  For example, there may be limited metallurgical testing, or limited geotechnical investigations; or the resource is largely inferred.
Not all PEA’s are equal (see “PEA’s – Not All PEA’s Are Created Equal”).  A large firm’s application of limited data may be no more accurate or defensible than a small firm’s use of the same data.
One of the purposes of an early stage study is to see if the project has economic merit and would therefore warrant further expenditures in the future.  An early stage study is (hopefully) not used to defend a production decision.  The objective of an early stage study is not necessarily to terminate a project (unless it is obviously highly uneconomic).
I have seen instances where larger firms, protecting themselves from  limited data, were only willing to use very conservative design assumptions in early stage mining studies. This may not be helpful to a small mining company trying to decide how to advance such a project.

Conclusion

The bottom line is that for early stage studies like a PEA, smaller engineering firms can do as good a job as larger firms.  However one must select the right firm.  Review some of their more recent 43-101 reports to gauge their quality of work.  Don’t hesitate to check with previous client references.
For the more advanced feasibility level studies, be wary if a smaller firm indicates they can do the entire study. Perhaps they can be responsible for some parts of the feasibility study as a sub-contractor to a larger firm. Managing these large study may be beyond their experience and internal capabilities.
Whether you are considering a small or large engineering firm, know their strengths and weaknesses as they will relate to the specific’s of your study.
In another blog post I have expanded the discussion about the importance of the study manager role. You can read that post at this link “Importance of a Study Manager – That’s the Key“.
Another blog post discusses undertaking studies using multiple engineering teams and the pitfalls to watch out for.  That blog post is at “Multi-Company Mining Studies Can Work Well…or Not“.
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Mining PEA’s – Is it Worth Agonizing Over Details

Date: May 5, 2015 Author: Ken Kuchling Comments: 3 Replies
Mining PEA
A previous blog post, titled “PEA’s – Not All PEA’s Are Created Equal”  , discussed that different PEA’s will consist of varying levels of detail.  This is dictated by the amount of technical data available (or not available).   But so too will different chapters in the same PEA be based on different data quality.
I have seen PEA’s where some of the chapters were fairly general, relying on limited data.  Meanwhile other sections in the same study had a lot of depth and detail.   Does it make sense to use varying detail in a study?  Detailed work cost more money, but is it wisely spent money?

The level of detail justifiable

If the Resource supporting the PEA mine plan is largely Inferred material, then the mine design and production plan will have a significant degree of uncertainty.  So there is not a lot of justification for other engineers to prepare a detailed tailings design associated with that mine plan.
Similarly there is little value in developing a very detailed operating cost model or cashflow model for a study that has many underlying uncertainties.  Certainly an IRR to two decimals is impressive, but unwarranted.  Overly detailed work may be a waste of time and money, adding to the PEA duration, increasing engineering costs, and giving the unintended (or maybe intended) impression that the study is more accurate than it really is.
Different levels of detail in the same study can crop up when diverse technical teams are each working independently on their own aspects of the study.   Some teams may feel they are working with highly accurate data (e.g. a production tonnage) when in reality the data they were provided with is still highly speculative.

Conclusion

The bottom line is that it is important for the Study Manager and project Owner to ensure the entire technical team is on the same page.
The team should understand the type of information they are working with, to ensure the technical detail in the final study is consistent throughout.
Experienced reviewers will recognize where the key data gaps are in a study.  Hence they may view the entire study with that in mind regardless of how detailed some of sections in the report appear to be.
You can read more on the subject of uncertainty in PEA’s in the previous blog post at this link “Mining PEA’s – Not All PEA’s Are Created Equal“.
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.   The entire blog post library can be found at https://kuchling.com/library/
For some free mining calculator apps, including project timelines and a simplified cashflow modeller, check out this website https://sites.google.com/view/drillingdown
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Multi-Company Mining Studies Can Work Well…or Not

Date: May 4, 2015 Author: Ken Kuchling Comments: Leave a reply
Mining studies
These days most, if not all, economics mining studies rely on a engineering teams comprised of participants from different consulting firms or from different regional offices of the same firm.   This approach gives the opportunity to use specific experts for different aspects of the study.
My recollection is that many years ago larger consulting firms would offer to do an entire study in-house. They would have the in-house team to cover almost the entire study. That approach seems to have changed and now the multi-company path is the norm.
This approach is partly being driven by the clients who wish to use specific consultants they are familiar with and have existing relationships with.
In some instances, larger firms may still make the argument they can take on all of the project scope themselves.  However one must reflect on such offers.  The danger being a less qualified technical team seconded from offices that are not busy.  Possibly you won’t get the best team; you  get who is available.
In many multi-company studies, it is not uncommon that few of the team members have ever worked together before.  It may be a consultant’s team building exercise right from the start.
I have had both good and bad experiences with these types of engineering teams.  Some of them work very well while others floundered.  Even when working with different offices of the same firm, things may not go as planned.

The Study Manager is Key

To have a successful mining study team, in my experience the two key factors are;
  1. The competency of the Study Manager;
  2. The amount (and style) of team communication.
The Study Manager is vital to keeping everyone working on the same page and ensuring timelines are met.   A single team member delaying their deliverables will delay others on the team.
Some consulting firms have multiple projects underway at the same time.  Unexpected delays in one study may cause them to shift idle personnel onto other studies.  Unfortunately sometimes it is difficult to bring the team back together on the original study at a moment’s notice.
The Study Manager must ensure that everyone understands what their deliverables are.   Generally this is done using a “Responsibility Matrix”, but these can sometimes be too general.
Where cost estimation is involved, the Responsibility Matrix should be supported by a Work Breakdown Structure (“WBS”) assigning the costing responsibilities.  Given that the contentious parts of many studies are the capital and operating cost estimates, I personally view the WBS equally as important as the Responsibility Matrix.
Team communication is vital and there are different ways to do it.   Weekly or bi-weekly conference calls work well but these need to be carefully managed.  With a large team on a conference call, there is a fine line between getting too much technical detail versus not enough detail.
On some studies I have seen a weekly call restricted to one-hour long and then everyone flees until next week’s call.  At the end of these conference calls, one might have an uneasy feeling of it being incomplete. Perhaps people were not clear on something but hesitated to ask become the one-hour time limit is up.   In such cases it is important for the relevant parties to continue on or to have a separate call.

Make it important to  speak up

The bottom line is that multi-company teams will work fine as long as the study manager is capable.  Its not a simple task, and not everyone can do it well.  However everyone (client and the other team members) appreciate working under a really good study manager.
In another blog post I have expanded the discussion about the importance of the study manager role.  You can read that post at this link “Importance of a Study Manager – That’s the Key“.
In another blog post I have gone into a bit more depth on the role a Work Breakdown Structure plays.   You can read that post at this link “Work Breakdown Structures – Don’t Forget About The WBS“.
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Mining PEA’s – Not All PEA’s Are Equal

Date: April 30, 2015 Author: Ken Kuchling Comments: Leave a reply
Mining Preliminary Assessments
A Preliminary Economic Assessment (“PEA”) is defined by NI 43-101 as “…a study, other than a pre-feasibility or feasibility study, that includes an economic analysis of the potential viability of mineral resources”.  The term “other” is fairly broad which provides plenty of flexibility.  While there are generally accepted industry norms for a pre-feasibility (PFS) or feasibility study (FS), the mining PEA can actually have a broad technical scope.  Some are more complicated than others.
Some PEA’s may have mine plans and production schedules based largely (or entirely) on Inferred resources.  Other PEA’s may rely on higher proportion of Measured and Indicated resource.
Some PEA’s might be based on a large database of metallurgical test work and site information.  Others may rely on very preliminary met data on a few ore types and thus require assumptions regarding that data.
Some PEA’s are able to incorporate information from advanced socio-environmental activities while other PEA designs may not have access to community feedback and initial concerns.
There seems to be some opinion that PEA studies are not worth the paper they are written on.  I would suggest that one should not assume that all PEA’s are equal in thoroughness and technical support.   Investors view a PEA as a measure of the value of the project. The geologists and engineers doing the PEA’s tend to view them as a document simply to support a decision whether to spend more money on the project (are they naive maybe?).  The companies themselves view the PEA as helping to address both issues.

Sequential PEA’s

The PEA is developed at a fairly early stage in the project life.  The initial PEA may be superseded with a series of updated PEA’s as more information is collected.  Why is this done?
Perhaps companies feel that shareholders will appreciate being updated on positive project growth.  More drilling means more tonnes, and hopefully more revenue.
The sequential PEA approach is a way for companies to continue advancement of the project without making the costly step to a Pre-Feasibility study or more expensive Feasibility study.
Maybe the project size is still growing and a Feasibility study locking in a design at this time would not consider the true potential, hence pushing for the sequential PEA approach.
The downside of the sequential PEA approach is that investors may get tired of hearing about PEA after PEA.  They may want to see big steps towards a production decision and not baby steps that consume time and money.  They ask themselves “How long can these guys keep studying this project?”.

 

There is no right or wrong as to what constitutes a PEA.

The securities commissions and NI43-101 consider that the cautionary language is an important component of any PEA Technical Report.  They may red-flag it if cautionary language not in all the right places (that’s why you see it so often).
For example the typical “The reader is cautioned that Inferred Resources are considered too speculative geologically to have the economic considerations applied to them that would enable them to be categorized as Mineral Reserves, and there is no certainty that value from such Resources will be realized either in whole or in part.”
That cautionary statement is focused on the Mineral Resource, but there is no mention of all the other speculative assumptions that may have been used in the PEA.  For example, the Inferred resource may not be that significant, however the lack of metallurgical test work might be a more significant uncertainty.  Therefore always visualize the cautionary language in sections that don’t have cautionary language.   To better understand this, always read the Technical Report sections pertaining to risks and opportunities (and recommendations) for a more complete picture of the entire report (usually Sections 25 or 26) .

Conclusion

The bottom line is that when reviewing a PEA report, be aware of all the uncertainties and assumptions that have been incorporated into the study. Each PEA is unique with respect to this.    The study may be well founded or built on a shaky foundation.
Often it seems that share prices do not move much with the disclosure of a new PEA.  There is a lack of confidence in them.  Conversely, one also hears that it is better for future financings if a mining project has at least reached the PEA stage.  PEA’s … we either hate them or love them.
It may help to develop your own personal checklist to identify the quality of data used in different parts of the PEA study.  This may help you understand where data gaps may exist.
In another blog post I discuss how it is important for the Study Manager and project Owner to ensure the entire technical team is on the same page and understands the type of information they are working with.   The technical detail in the final study should be consistent throughout.   You can read that blog at “PEA’s – Is it Worth Agonizing Over Details“.

 

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.   The entire blog post library can be found at https://kuchling.com/library/
For some free mining calculator apps, including project timelines and a simplified cashflow modeller, check out this website https://sites.google.com/view/drillingdown
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4 Mining Study Types (Concept to Feasibility)

Date: April 29, 2015 Author: Ken Kuchling Comments: 2 Replies
Over my career I have been involved in a range of mine studies, from desktop conceptual to definitive feasibility.    Each type of study has a different purpose and deserves a different level of input and effort  Each can have significantly different costs to undertake.
I have sat in on some junior miner management discussions regarding whether they should be doing a PEA or a Pre-Feasibility Study, or a Feasibility instead of a Pre-Feasibility Study.    Everyone in the room had their opinion on how to proceed based on their own reasoning.   Ultimately there is no absolute correct answer but there likely is one path that is better than the others.  It depends on the short and long term objectives of the company, the quality of data on hand, and the funding available.

4 types of mining studies

In general there are 4 basic levels of study, which are listed below.  In this blog I am simply providing an overview of them.  On the web there are detailed comparison tables, but anyone can contact me at KJKLTD@rogers.com for an a full copy of my table (an excerpt is shown below).

Four Studies Table

1. Desktop or Conceptual Mining Study
This would likely be an in-house study, non-43-101 compliant, and simply used to test the potential economics of the project.  It lets management know where the project may go (see a previous blog at the link “Early Stage “What-if” Economic Analysis – How Useful Is It?”.    I recommend always doing a desktop study, and preparing some type of small internal document to summarize it.  It doesn’t take much time and is not made public so the inputs can be high level or simply guesses.  This type of early stage study helps to frame the project for management and lets one test different scenarios.
2. Preliminary Economic Assessment (“PEA”)
The PEA (or scoping study) is generally 43-101 compliant and presents the first snapshot of the project scope, size, and potential economics to investors.  Generally the resource may still be uncertain (largely Inferred classification), capital and operating costs are approximate (+/- 40%) since not all the operational or environmental issues are known at this time.   Companies should avoid promoting the PEA as an “almost” feasibility level study.  Investors should not view the PEA as a feasibility study just because it is 300 pages long with a lot of tables and charts.

Don’t Announce a PEA Until You Know the Outcome

I also recommend not announcing the start of a PEA until one is fairly confident in what the outcome of that PEA will be.   A reasonable desktop study done beforehand will let a company know if the economics for the PEA will be negative, marginal, or great.  I have seen situations where companies have announced the start of a PEA and then during the course of the study, things not working out economically as well as planned.  The economics were poorer than hoped and so a lot of re-scoping of the project was required.  The PEA was delayed, and shareholders & analysts negative suspicions were raised in the meantime.
The PEA can be used to evaluate different development scenarios for the project (i.e. open pit, underground, small capacity, large capacity, heap leach, CIL, etc.).  However the accuracy of the PEA is limited and therefore I suggest that the PEA scenario analysis only be used to discard obviously sub-optimal cases.  Scenarios that are economically within a +/-30% range of each other many be too close to discard at this PEA stage.  This is where the PFS comes into play.
3. Pre-Feasibility Study (“PFS”)
The PFS will be developed using only Measured and Indicated resources (no Inferred resource allowed) so the available ore tonnage may decrease from a previous PEA study.  The PFS costing accuracy will be greater than a PEA.  Therefore the PFS is the right stage to evaluate any remaining mine development optional scenarios.  Make a decision on the single path forward going into the Feasibility study.

Use the PFS to determine the FS case

More data will be required for the FS, possibly a comprehensive infill drilling program to upgrade more of the the resource classification from inferred to indicated.  Many companies, especially those with smaller projects might skip the PFS stage and move directly to Feasibility.  I don’t disagree with this approach if the project is fairly simple and had a well defined scope (i.e. mining method, throughput rate, site layout) at the PEA stage.
4. Feasibility Study (“FS”)
The Feasibility Study is the final stage study prior to making a production decision.  The feasibility study should preferably be done on a single project scope.  Try to avoid doing more scenario option analysis at this stage.
Smaller unsure companies should be careful about entering the FS stage.  Once the FS is complete, shareholders will be expecting a production decision.  If the company only intends to sell the project with no construction intention, they have now hit a wall.  What is there to do next?

Sometimes management feel that a FS may help sell the  project.

I don’t feel that a FS is needed to attract buyers and sell a project.  Many potential buyers will do their own in-house due diligence, and possibly some alternate design and economic studies.   Likely information from a PFS would be sufficient to give them what they need.  A well advanced Environmental-Socio Impact Assessment may provide more comfort than a completed Feasibility Study would.  Based on my review of project timelines, the Feasibility Stage is generally a significant trigger for someone with the intent to build the mine themselves.   To learn more about Mine Builder vs Mine Vendors, one can find a blog at this link.

Conclusion

executive meetingMy final recommendation is that there is no right answer as to what study is required at any point in time.  Different paths can be followed but consideration must be given to future plans for the company after the study is completed.   Also consider what is the best use of shareholder money?
Company management may see pressure from retail shareholders, major shareholders, financial analysts, and the board of directors to “do a study”.  Management must decide which mining study path is in the best longer term interests of the company.  Maybe no study is warranted.
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.   The entire blog post library can be found at https://kuchling.com/library/
For some free mining calculator apps, including project timelines and a simplified cashflow modeller, check out this website https://sites.google.com/view/drillingdown
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Early Stage “What-if” Mine Economic Analysis – Its Valuable

Date: April 27, 2015 Author: Ken Kuchling Comments: Leave a reply
Mining study economics
Over my career I have worked with large and small mining companies and seen how they studied projects and potential acquisitions.
Large mining companies have their in-house evaluation teams that will jump on a potential opportunity that comes around and start examining it quickly.  These evaluation teams may consist of a specialized head office group supported by people temporarily pulled in from their mining operations.
They are experienced at what they do and can provide management with solid advice even if working with only limited data.  This help management decide very early on whether to further pursue the opportunity or walk away immediately.
Early stage economics are normally part of this evaluation approach.   Although they are not correct all of the time, more than often they save their company from wasting money on projects unlikely to fly.
However if you are a small mining company, what are your options?
You don’t have an in-house technical team sitting around ready to go.  Management still needs to know if this project has a chance.  If the project is early stage, sometimes management thinks its fine to take a gamble, acquire the project, and then put money into the ground rather than spending on early studies.

It is possible to do both

Management and the exploration team usually have a vision for their projects, even those projects with only limited information.   Each person may have a different opinion on the potential size and scope of what may ultimately exist there.  However the question is whether any of those visions have sufficient accuracy to warrant spending more shareholder money on the project.
Some of the junior mining management teams that I have worked with have found it beneficial early on to have a basic internal cashflow model on hand.   If properly constructed, these are simple to tweak to examine “what-if’s” scenarios.  Input the potential deposit size and mine life, potential head grades, expected metallurgy, and typical costs to see what the economic outcome is.  Does this project have a chance and, if not, what tonnage, head grade, recovery, or metal price is required to make it work?   The simple cashflow model can tell you all of this.

Early stage modelling adds value

The tangible benefits to very early financial modelling are:
  • It helps management to conceptualize and understand their project.  If done honestly, it will reveal both the opportunities and threats to success.
  • It helps management to understand what technical parameters will be most important for them to resolve and what technical factors can be viewed as secondary. This helps guide the on-going exploration and data collection efforts.
  • Periodically refreshing the economic model with new information will reveal if the economic trends are getting better or worse.

Its not 43-101 compliant

I must caution that this type of early stage economic analysis is not 43-101 compliant and hence can not be shared externally, no matter how much one might wish to.
Another caution is that in some cases these early stage un-engineered projections become “cast in stone”, with management treating them as if they are accurate estimates.  Then suddenly all subsequent advanced studies must somehow agree with the original cost guesses, thereby placing unreasonable expectations on the project and the people doing the work.
The early stage economic models can consist of simple one-dimensional tables using life-of-mine tonnages or two-dimensional tables showing assumed annual production by year.  Building simple cashflow models may take only 2-3 days of effort.  That is not an onerous exercise compared to the overall benefit they can provide.
The bottom line is that it is useful to take a few days to develop a simple cashflow model.  “Simple” also means that management themselves can tweak the models and don’t need to be modeling expert on hand at all times.  “Simple” means the model should be well.  In another block post I discuss why to avoid demonstrating one’s Excel skills in building models. Read more on that at this link  Financial Spreadsheet Modelling – Think of Others.
Most companies have a CFO that can easily undertake this type  of modelling, with the help of some technical input.  Be careful though, often CFO’s take the simple cashflow model to an unwarranted level of complexity.
The simplest of all models is the one-dimensional approach.  To learn more about the concept behind a simple 1D financial models, read the blog post “Project Economics – Simple 1D Model” .
The entire blog post library can be found at this LINK with topics ranging from geotechnical, financial modelling, and junior mining investing.
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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