Answer and Explanation:
The computation is shown below;
a. The Cost of Copper Mine is Â
Mining Site $1,300,000
Development Cost $660,000
Restoration Cost $324,115
Cost of Copper Mine $2,284,115
working note
Restoration Cost  Â
$360,000 × 20% =  $72,000
$ 4,60,000 × 45% = $207,000
$ 6,60,000 × 35% = $231,000
Total $510,000
Present Value of Restoration Cost = $3,24,115
($510000 × 0.63552)  Â
Present Value of $ 1, n = 4, i=12%
b. The journal entries are given below:
1 Copper mine $2,284,115 Â ($1300,000 + $6,60,000) Â
   To Cash  $1,960,000 Â
   To Assets retirement liability  $324,115 Â
(Being acquisition of mine recorded) Â Â
2 Equipment $180,000 Â
    To Cash $180,000 Â
(Being Equipment purchased recorded) Â