can you help me understand this?

Bunker Hill Mining Company has two competing proposals: a processing mill and an electric shovel. Both pieces of equipment have an initial investment of $656,853. The net cash flows estimated for the two proposals are as follows:

Net Cash FlowYearProcessing MillElectric Shovel1$210,000$263,0002187,000244,0003187,000225,0004149,000231,0005113,000695,000782,000882,000

The estimated residual value of the processing mill at the end of Year 4 is $260,000.

Present Value of $1 at Compound InterestYear6%10%12%15%20%10.9430.9090.8930.8700.83320.8900.8260.7970.7560.69430.8400.7510.7120.6580.57940.7920.6830.6360.5720.48250.7470.6210.5670.4970.40260.7050.5640.5070.4320.33570.6650.5130.4520.3760.27980.6270.4670.4040.3270.23390.5920.4240.3610.2840.194100.5580.3860.3220.2470.162

Determine which equipment should be favored, comparing the net present values of the two proposals and assuming a minimum rate of return of 12%. Use the present value table appearing above.