Answer:
The Journal entries are as follows:
(i) On January 1, 2017
Plant Assets A/c Dr. $600,000
To cash $600,000
[To record the depot]
(ii) On January 1, 2017
Plant Assets A/c Dr. $41,879
To To Asset retirement obligation $41,879
[To record the Asset retirement obligation]
Missing information: Based on an effective-interest rate of 6%, the present value of the asset retirement obligation on January 1, 2017, is $41,879.