StockGuru Canada

Valuation of a Mine

Mines are opened up by level, and are divided into blocks.  The shape of the blocks and not always geometrical, but the volume of these blocks can be approximated.

The average width of the ore is the arithmetical mean of the width of the sample sections.  The cubic foot contents is the with multiplied by the area of the longitudinal section.

Three Methods of determining the specific volume of ores

1.            Find the true specific gravity of the specimens – very expensive

2.            By determining the weight of quantities broken – would require several tests

3.            Approximation based  on the specific gravities of the predominant minerals in the ore.  Ores have a mixture of many minerals, but a general inspection of the compactness of the ore give a fairly reliable basis for approximation.

                                                                                Weight per cubic feet                    Cubic Feet Per Ton

To calulate the amount or mineral multiply the percentage of the ore by the weight of the ore.

A gold ore sample of 95% quartz and 5% iron pyrite.

The weight of the ore is as follows.

Quartz, 95% x 12.07 = 11.47 cubic feet per ton   

Iron Pyrite, 5% x 6.40 =.32 cubic feet per ton