PFS - DFS22 May 2020 12:56
A couple of days ago some were discussing the need for PFS and DFS. I've been busy since but thought it may help to explain their differences.
Consider the PFS as a broader brush look at the project viability. The entire project is looked at from a +/- 30% cost perspective i.e how the mine itself may be accessed and worked in the most optimal way, the size and budget prices of machinery needed to get the ore (from underground in Alpala instance) to the surface, conceptual engineering of crushing plant, conveying, grinding mills, how many ktonnes of steel etc. Also the tailings dam, infrastructure, roads, water supply volumes etc. It takes may thousands of man hours to work through the various options for these in addition to which the metallurgy needs to be more closely studied by further bulk sampling and testing. At the end of all this you have a reasonable idea of the way you might approach the mining and blending of the various grades of ore over the life of the mine and how you will process them, for how many, and where you will put the accommodation and messing facilities, where the power lines and roads will run etc etc etc.
The DFS then narrows all the above down to a project plan with costs narrowed to +- 15%. More detailed mine planning, detailed engineering and firm $ for equipment is sorted. I have only mentioned a few of the components of the feas studies and there are many more not mentioned herein. This takes for a project of Alpala scale many 1000s of manhours hence the lengthy timeframes to achieve. At the end of this process you have a study which demonstrates the bankable feasability /viability of the project.