Sampling and milling tests of chromite ore in the Hindubagh mining district, Quetta Division, Pakistan

Milling tests on chromite ores and analyses of cleaned chromite from the Hindubagh mining district show that gravity concentration methods can raise the grade of subcommercial ores to 48 percent Cr₂0₃ or more. The Cr:Fe ratio in concentrates from the Nasai subdistrict, however, will be less than the conventional commercial standard of 3:1. A Cr:Fe ratio of 3:1 could be produced by blending low-grade and high-grade ores, but for the district as a whole, concentrates averaging 50-52 percent Cr₂0₃ and 2.8:1 Cr:Fe ratio probably would yield the largest economic returns. Although not readily marketable now, ores and concentrates of this grade will be used increasingly in the near future.