But a surprise rally in coal prices has revitalised mining companies knocking on his door again, and the interest has reached fever pitch this week.
Mr Wall's company Hassalls will stage one of the biggest mining equipment auctions in years on Wednesday, when thousands of items from Anglo American's Drayton coal mine in the Hunter Valley go on sale in a two-day auction.
Hassalls' usually sells second-hand equipment via its website, but Mr Wall said demand was strong enough to attract buyers to the Drayton mine site near Muswellbrook, where the equipment will be sold on the spot to the highest bidder.
"We would not have held an auction one year ago for this equipment, the market was that soft," he said.
The auction will include about a dozen dozers, about 40 Nissan Patrol vehicles and 33 large Caterpillar dump trucks that are expected to sell for between $300,000 and $500,000 each.
Mr Wall says a 550 tonne digger is the largest and most expensive of the 1100 lots on sale over the two days.
"This is big equipment that is hard to move so the miner doesn't want to waste money moving equipment, so the buyers are coming to the mine site; the mountain is coming to Muhammad rather than the other way around, so to speak."
"We have had a lot of inquiry from the west coast and east coast of Australia, as well as offshore, the US, Dubai, New Zealand," he said.
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