Item

Ore Deposit and Ore Type

Endogenic Deposit

rich ore

lean ore

ω(Cr2O3)%

cut-off grade

≥25

≥5～8

Min grade

≥32

≥12

Minimum minable thickness

（m）

0.3～0.5

1.0

the rock eliminating thickness of ore （m）

0.5

1.0

Remark 1：Metallurgical will take use of chromite ore or concentrate, when pyrogenic process smelting ω(Cr2O3)／ω(FeO)>2, but wet process smelting is not limited. ω(SiO2)≤8％(Using ore thermal method for smelting high-carbon will also not be limited.)
Remark 2：Refractory chrome ore and concentrates，ω(SiO2)≤10％，ω(CaO)≤3％，ω(FeO)≤14％
Remark 3：Chemical chrome ore and concentratesω(SiO2)≤8％，ω(A12O3)≤15％。
Remark 4：Diabase with chrome ore，ω(Cr2O3)≥(10％～20％)，ω(SiO2)<10％。
Remark 5：The total amount of platinum group elements associated need to choose chromite (0.3～0.4)×10-6, should be assessed.
Remark 6：The selection of lean ore or cut off grade is generally twice the tailings grade.
Remark 7：The min mining thickness of bonanza : single seam 0.5m, complex seam for each monolayer is 0.3m.