South32 Ltd. secured approval for two more 305-meter-wide longwalls at its Dendrobium coal mine, part of the Illawarra operation in New South Wales, Australia, The Sydney Morning Herald reported Dec. 26.

The authorization will allow the mining major to extract coal from underneath the Metropolitan Special Area created to protect the waters of the Avon, Cataract, Cordeaux and Nepean reservoirs.

However, the company is only allowed to cut the two new longwalls to a height of 3.9 meters, as opposed to 4.6 meters permissible for the current five longwalls in order to reduce the risk of caving in that can disrupt surface and ground waters.

The miner noted that the approval will help secure up to 400 jobs.

According to the publication, the latest expansion was allowed despite incomplete independent studies on groundwater impacts as well as the company declining to share findings of a 2012 report with the government.