
Mining Cashflow Sensitivity Analyses – Be Careful


I 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.
Changes in economic parameters would impact the original pit optimization used to define the pit upon which everything is based.
I have heard from geologist colleagues that financing grass-roots exploration is still extremely difficult. That is unless company management has had past successes or is well connected to the money scene.You don’t want to always change management
Keep plans realistic and achievable
The bottom line is that in order for a project (and the management team) to get serious attention from potential investors is to make sure there is a realistic view of the project itself and have a realistic path forward.
Think about the level of detail justifiable
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 and understands the type of information they are working with. The technical detail in the final study should be consistent throughout.
The NSR represents a $/tonne recovered
Generally I have no major concerns with the metal-equivalent approach at the resource estimate stage. However from an engineer’s view, an equivalent grade does not provide a meaningful representation of the ore quality.Using the NSR approach, the operating margin per block is evident.
Pit Optimization
Since the NSR block value is mainly used for the ore/waste cutoff, I don’t feel it is necessary to get overly detailed in its calculation. The cashflow model should always calculate revenues from individual metals rather than using the block NSR value.
Some PEA’s might be based on a large database of test work and site information while others may rely on very preliminary data and require design projections based on that data.Sequential PEA’s
The sequential PEA approach is a convenient way to continue advancement of the project without making the step to a Pre-Feasibility study or bigger step to a Feasibility study. Maybe the project is still growing in size and a feasibility study at this stage would not be presenting the true potential, hence the updated PEA.
There is no right or wrong as to what constitutes a PEA.
The securities commissions consider that the cautionary language an important component of the PEA Technical Report and may red-flag it if it’s not in all the right places. However this cautionary language is generally focused on the resource.Conclusion

4 types of mining studies
Don’t Announce a PEA Until You Know the Outcome
Use the PFS to determine the FS case
Sometimes management feel that a FS may help sell the project.
Conclusion
My 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?