Took me 2 months of background play to finally get to the mountains. The mountain contains $1.0e12. Each day takes away about $1.0e8. Straight math show it will take about 9999 days to finish.
Right now new minions cost so much, while the benefits are negligible. That said, I will give it the benefit of of doubt and estimate though out game play it will double my money per day to $2.0 e8. That means 4499 days to finish. Also the goblin achievement and, as mention by others, property do not seem to work.
Yeah.