Trader: "...As a non-geo, can you explain to me why the mine plan takes so long to devise. I understand that there are a lot of different issues involved but with the power of computers and software these days, I would think that it shouldn't be as massive an undertaking as it seems to be."

I am not sure that my ideas on what is involved in a mine plan are that credible or helpful but here is my understanding. SC is huge. Mineralization extends about 2.5km north to south (DDH 425 to just short of DDh 421) so there are a lot of problems taking 3 to 6 inch drill core in a few spots to confidently predict the rock's characteristics over such a vast area. How many geotechnical drills do we have? The economics and safety issues require confidence. Where you don't have confidnence you need to compensate with more conservative engineering practices such as wider benches and shorter drops to lower the overall angle of the pit walls. The NW wall may be in the order of 1000 to 1500m in height (1 to 1.5km, 0.6 to 0.9 miles) above the floor of the final pit. Imagine how small you would feel looking up at almost a mile high wall of rock!

Mt Lacasse is steep in the NW corner of our deposit. Increasing the slope of the ground exacerbates the engineering issues for safety and economics.

Engineers need to sign off on the plans they devise and are accountable for them. Engineers (in BC anyways) wear an iron ring on their pinky finger made from steel recovered from a vancouver bridge (the Second Narrows bridge) that collapsed during construction and killed a number of workers. The ring serves to remind engineers that their plans matter to people's lives. Further layers of conservatism and restraint.

Poryphry deposits (SC included) tend to be quite complex geologically (mineralization, faulting etc). Complexity leads to uncertainty leading to more restraint. Poryphries also tend to be located in sizmicly active areas (ring of fire); earth movements are not an exact science. More conservatism.

Lowish grade deposits like SC don't have a lot of wiggle room for fancy, expensive engineering options - staggering amounts of material needs to be moved from point A to point B. Blowing up strong, heavy rock and transporting it cheaply only offers so many alternatives. Digging up to 500-600m of rock takes time and time is money. Stockpiling low grade ore for processing at a later date takes time, money and space. More constraints.

SC does have plenty of barren rock and also some acid generating rock. Barren rock needs to be moved and wasted somewhere cheap and permanent. Constraint. Acid rock needs to be isolated from streams and preferably covered by water to prevent oxidization and leaching. Constraint.

Ramp angles out of the pit for ore trucks need to be such that laden trucks can crawl out. And wide enough to safely handle very large machines. Meanwhile other folks are in the same hole blowing stuff up and loading empty trucks.

All of these constaints (and more for sure) need to work with the lay of the mineralization, and the surrounding landscape. It isn't all in a neat funnel shape like a completed open pit we all can imagine.

I imagine that the engineers start with a resource model (RE) and try a best guess at how to mine it in a computer model with all of the constraints in mind. I don't know what happens with the computer models at this point; do they run minutes or days to spit out an optimized plan? How many iterations do they do? How good are they at modeling reality? Computer models are only as smart as their worst section of computer code. The output from the computer model then needs to be scrutinized and annointed by a qualified human (qualified professional).

All this is from the top of my unqualified head...