If they are piling dirt there, they are building an levy for the geo-tubes. They previously were using two for the test. They will probably install the other two.
We can actually get a production rate once the truck(s) are returning from the mine loaded. Take the truck capacity in LCY(found on CAT's website); multiply by number of cycles per day; multiplied by the estimated gold content in the soil; multiplied by an efficiency factor (of the worst piece of machinery they use). The bottle neck will be the excavator(s) so noting the ID numbers on the trucks is key to knowing how many are being used. This is a little ahead of the game, but once they're running trucks, a good ol' calculator and a stopwatch is all we need to determine production rates.
pure speculation, but they might be getting rid of the processed soil to make room for new stock piles. The haul road has been improved for use by heavy equipment. I'm currently in the process of installing an 8in lift and 35in tires on my jeep. So I can and WILL drive all over the area in a couple weeks if necessary. There won't be one area I won't be able to go within a 10mi radius of the mill ;)