DCHP-1 Online
high-grade ((adj.)) Mining 
adj. denoting or containing gold-bearing ore of a high assay value.
See also: high-grade ((1)) ((n.)) (def. 1)
- 1910 . . . they knew of a ledge of high-grade, free-milling quartz somewhere out there in the Land Back of Beyond.
- 1913 . . . Klondike . . . now considered a fairly good creek with, if not high-grade dirt, plenty of paying stuff.
- 1958 At one property The Northern Miner was shown no less than 10 sample bags containing high grade gold ore that has been recovered this year.
- 1910 . . . they knew of a ledge of high-grade, free-milling quartz somewhere out there in the Land Back of Beyond.