GSI 2016 Paper III Q7 (b) Calculate ore reserve of a 5 m thick ore blocked out between two levels, separated by 30 m, and ready for immediate extraction. The length of the ore block is 40 m and the bulk density of the ore is 2-73 gm/cc. Assuming 0-63% average grade of copper, how much copper metal can be obtained from the block with 90% recovery ?

 Solution :- 

Given :- Thickness = 5m,        Length = 40m        Width = 30m        Density = 2.73 gm/cc

Assay Value = 0.63%

1)  Volume  =  5 X 40 X 30 = 6000m³

2)  Mass  =  Volume X Density

                =   6000 X 2.73

                =   16,380 Tonne

3)  Metal Content from 90% recovery 

     

     16,380 Tonne     =   100 % mass

            1%               =   163.80

      Metal Content    = 163.80  X  0.63

                                 =  103.194 Tonne

Total 100% recovery  =  103.194 Tonne

                            1%   =  1.03

                                     = 1.03 X 90

                                     = 92.7 Tonne