CALCULATE:

The monthly tonnage to be mined from each of the two reefs and for how long.

The average value of the 180 000 tons per month mined in (a) above.

If an average value of 15,50 g/t is required from the combined reefs from day one and

the monthly tonnage increased to 200 000 tons, what tonnage must each reef

contribute to this same monthly rate of stoping?

A preliminary assessment of a new mine from prospecting and development information indicates that the mine's base area contains 51 000 000 tons of payable reef A which is expected to be mined at an average value of 16,80 g/t and 38 720 000 tons of payable reef B which is expected to be mined at an average value of 12.90 g/t. For the first five years of the mine's life only reef A will be mined at the value of 16,80 g/t and at a rate of 120 000 tons per month. Thereafter both reefs will be mined simultaneously at a rate of 180 000 tons per month. The stoping will be in such a proportion that both reefs will be mined out simultaneously at the end of the mine's life