Kepco has told the NSW Land and Environment Court the IPC made errors of law when it refused the mine in September for reasons including that future generations will bear the costs for today's economic benefits.

The company, which paid more than $400 million for the mining lease in 2010, said the IPC erred because it should only have considered if the Bylong proposal would maintain or enhance the environment's health, diversity or productivity for future generations.

Kepco said the IPC also erred when it failed to refer the application to the Minister for Regional Water for advice before making its determination.

Kepco told the IPC it spent $750 million in total in its bid to develop a new open cut and underground coal mine in the Bylong Valley between Denman and Mudgee to produce up to 120 million tonnes of coal over 25 years for the Korean domestic energy market.

It would create more than 800 direct and indirect jobs, with nearly $280 million in royalties to the NSW Government and $600 million in annual business turnover, Kepco said.

The refusal prompted a NSW Minerals Council campaign against the commission, and accused it of being "the faceless IPC" which "represents everything that is wrong with the NSW planning system".

The council accused the NSW Government and Planning Minister of "doing nothing" about a mine refusal. The campaign resulted in the government ordering a review of the commission and putting forward legislation to prevent greenhouse gas emissions burnt overseas from being considered during mining assessments.

In its application for a judicial review Kepco said an approved mine would "Assist Australia to continue to meet the international demand for thermal coal for at least the next 25 years, during which time it is expected there will continue to be strong world demand for coal for electricity generation."

In its final determination the IPC gave a number of grounds for refusing the mine, including its impacts on groundwater, that it was not satisfied Kepco could rehabilitate more than 400 hectares of strategic agricultural land impacted by the mine and unacceptable impacts on the heritage value of the property Tarwyn Park.

Kepco had also failed to provide the IPC with enough information to form a view on the proposal's Aboriginal heritage impacts, and there was a "reasonable level of uncertainty" about the economic benefits, the IPC said.

The company has asked the Land and Environment Court to find the refusal invalid and of no effect, and to return it to the IPC for a "redetermination in accordance with law".

The matter is listed with the court on February 14.