Question 5
[11 Marks]
An engineer for a mining company is directed to examine a special property and to advisethe
company's management as to its potential value. Estimates of the ore readily available are 800
000 tonnes and she bases her evaluation on that figure. Mining equipment available will meet an
annual production estimated at 75 000 tonnes of ore. It is estimated that gross income will be
$15.75 per tonne of mined ore and that mining operations, transportation and smelting costs will
total $7.75 per tonne of ore. Administration and other expenses are estimated to be $55 000 per
year.
(a) What would the engineer report as expected life of mine?
[2]
(b) If the interest for the project was 7.5% per year compounded annually,
(i) Calculate the probable present value of the property.
[5]
(ii) Would the engineer be justified in recommending that the company invests $ 10
million in the property? Show your working and state your reasons clearly. [2;2]
Question 6
[5]
Maintenance costs for a new piece of mining equipment which costs $150,000 are expected to
be $25,000 in the first year, rising by $1,000 per year every year thereafter. The machine has a
life of 5 years and interest is 10% annually. The salvagevalue is $55 000.
What is the net present value of these costs?
[5]
Question 7
[5 Marks]
A certain gold mine has a production capacity of 200 000 tonnes per month at an ore grade of
3.5 git. The mill recovery is 86% while that for the subsequent smelting and refining is 90%. If
the mining and overall processing costs are $40 and $30 per tonne ofore respectively, while tax
is 20% of profit; Assume 1Oz = 30g.
What is the after tax income of the operation if the gold price is US$1700/Oz?
[5]
5