Okay, time to kick this up to the next level. Digging on TA is obviously not the best way for a high-luck digger to maximize his silvers earned from a single load of digables. At 150 luck, I'm digging 3 oreputty in 4 out of every five dig clicks, and since oreputty is the just 6th best silvers/kg digable for Prospector (he can't dig up silvers any more), he gets weighed down with the semi-valuable oreputty quite quickly.
Anyway, long story short: Prospector, level 39, 150 luck, 72 kgs pack capacity, Larkinor dark district:
2036 gold nuggets
57 diamonds
38 disprosiums
27 kithrills
28 centroliums
293 hyperiums
2,296,360 silvers when sold at 50%.
I had to sell this in 4 batches to avoid overloading on the silvers earned.
Sandy