Chinese Mining History in BC, Canada
During the late 19th century British Columbia, Canada Gold Rush Tulameen River area placer miners (other than gold) found in their sluice boxes a whitish heavy mineral that seemed to be new because no one knew anything about it.
Most of it was initially discarded but then some of the miners thought that it might still have some value so they cached it and buried it. Same as these Chinese miners. Or the Swede Johansson whose cache has not yet been found.
Later on, back East assayers told them that it is a valuable precious metal - Platinum (plus associated metals) so they kept it...