Description:  Slab of brown coarse-grained sandstone. Attached label reads "K6 sandstone.grit 'refractory ore' ~ 1% Cu (not extractable) Cupiferous wad &iron oxides. Kalengwa Open Pit. Zambia. Pres by Roan Consol Mines 22.8.72." Attached descriptive list from Roan Consolidated Mines Limited states "K6 'Refractory ore from footwall side of the orebody. Rock is a decomposed specularitic grit with interbeds of siltstone and sandstone, containing cupriferous wad and iron oxides assaying ½ - 1½% TCu. Refractory ore is ore containing copper in a mineralisation formand not amenable to normal extractive methods of metallurgy i.e. flotation (as for sulphides and sometimes higher grade oxides) and leaching (as for carbonate type mineralisation).