Answer:
Windhoek Mines, Ltd.
The net present value of the proposed mining project is:
=  ($232,950).
Explanation:
a) Data and Calculations:
Cost of new equipment and timbers = $500,000
Working capital required  = $100,000
Annual net cash receipts = $120,000
Cost to construct new roads in three years = $40,000
Salvage value of equipment in four years = $65,000
Estimated useful life of mine = 4 years
Working capital released in four years = $100,000
Required rate of return = 20%
                                                            Cash Flows   PV factor  Present Value
Cost of new equipment and timbers  $500,000      1               -$500,000
Working capital required                        100,000       1                 -100,000
Annual net cash receipts                       120,000     2.589            310,680
Cost to construct new roads in 3 years 40,000     0.579             -23,160
Salvage value of equipment in 4 years 65,000     0.482               31,330
Working capital released in 4 years     100,000     0.482              48,200
Net present value                                                                      ($232,950)