Net Present Value$-$Unequal Lives

Net Cash Flow

$\backslash$table$[[$Year$,$Processing Mill,Electric Shovel$],[1,$$$188,000,$$$235,000],[2,167,000,218,000],[3,167,000,201,000],[4,133,000,207,000],[5,102,000,],[6,85,000,],[7,73,000,],[8,73,000,]]$

The estimated residual value of the processing mill at the end of Year $4$ is $$240,000.$

Present Value of $$1$ at Compound Interest

$\backslash$table$[[$Year$,6\%,10\%,12\%,15\%,20\%],[1,0\mathrm{.}943,0\mathrm{.}909,0\mathrm{.}893,0\mathrm{.}870,0\mathrm{.}833],[2,0\mathrm{.}890,0\mathrm{.}826,0\mathrm{.}797,0\mathrm{.}756,0\mathrm{.}694],[3,0\mathrm{.}840,0\mathrm{.}751,0\mathrm{.}712,0\mathrm{.}658,0\mathrm{.}579],[4,0\mathrm{.}792,0\mathrm{.}683,0\mathrm{.}636,0\mathrm{.}572,0\mathrm{.}482],[5,0\mathrm{.}747,0\mathrm{.}621,0\mathrm{.}567,0\mathrm{.}497,0\mathrm{.}402],[6,0\mathrm{.}705,0\mathrm{.}564,0\mathrm{.}507,0\mathrm{.}432,0\mathrm{.}335],[7,0\mathrm{.}665,0\mathrm{.}513,0\mathrm{.}452,0\mathrm{.}376,0\mathrm{.}279],[8,0\mathrm{.}627,0\mathrm{.}467,0\mathrm{.}404,0\mathrm{.}327,0\mathrm{.}233],[9,0\mathrm{.}592,0\mathrm{.}424,0\mathrm{.}361,0\mathrm{.}284,0\mathrm{.}194],[10,0\mathrm{.}558,0\mathrm{.}386,0\mathrm{.}322,0\mathrm{.}247,0\mathrm{.}162]]$

$\backslash$table$[[,$Processing Mill,Electric Shovel$],[$Present value of net cash flow total,vdots,$$],[$Less amount to be invested,$$,$$$],[$Net present value,$$,$$$]]$

Which project should be favored?