In sulfide mining, the rejects are 25 percent larger than they were pre mining. This “swell factor” means a huge, above ground pile that won't fit in the pit. It is virtually impossible to bury or cover up the waste.
My thoughts on this are that space based ground penetrating radar systems will improve to the point we can find the intact magnetite meteors lodged in Earth's otherwise crystaline silicon surface and then mine them for what we need.
The sulfide meteors are a mess ~ but they're usually broken up with the metals leached out into "veins", or maybe even worse, scattered hither and yon over tens of thousands of square miles of disaggregated schist and clay ~ as valuable as this particular site is there are better sources, but we need to find them.