I saw burlap on the ground used in Tanzania, by the artisanal miners, to recover gold from days of stockpiled paygravel.  I had read about ground-sluicing by the 49ers and the long standing practice of using burlap in undercurrent sluiceboxes to capture the fine gold... not the sheep's wool golden fleece, but that would have worked too in my initial crude effort to capture native gold.  This to me is FUN!  Read the "Description" to see why.

Limerick Basin Ground Sluice