Whitehaven Coal is conducting the second phase of a business review to cut costs at its open cut mines and the Narrabri longwall operation after the company reported a half-year net loss after tax of $47 million.

The company blamed weak global coal prices, the unfavourable foreign exchange rate and increasing pressure on operating cash margins for the job losses.

It follows the shock decision to end a drivage contract at its Narrabri mine with Delta SBD nine months early.

The changes include amended mine plans that deliver reduced stripping ratios at both operations, allowing a reduction in total installed mining fleet by two 2500 excavators, one at Rocglen and one at Tarrawonga.

As a result, haul truck numbers at each site will be reduced by four – a total of eight across the group.

About 30 permanent Whitehaven positions and 10 contractor roles will be made redundant as a result of the decision. The redundancies impact Whitehaven’s mine operations and maintenance staff, as well as contractors.

Whitehaven said it had informed all employees, contractors and the mining union about the decision in relation to the decision, with further briefings for night shift employees later today, managing director Tony Haggarty said.

“While Whitehaven is a relatively low-cost opeerator, we are not immune from the continuing weakness in global coal prices, and are continuing to review our cost base on an ongoing basis,” he said.

“Our objective is always to keep our operations running safely, sustainably and profitably. The changes at Rocglen and Tarrawonga will mean that these operations remain viable at current coal prices.

“Reducing our workforce is a difficult decision to take. However, as part of the review process it became clear that decisive action needed to be taken in order to ensure our open cut business remained viable in the current low coal price environment.

“Notwithstanding today’s announcement Whitehaven will maintain its position as a major employer in the region with its ongoing open cut business, the world-class Narrabri underground mine and the major Maules Creek development expected to commence construction in the second half of this calendar year.”

Earlier this month the federal government approved Whitehaven Coal’s 70%-owned Tarrawonga coal mine expansion project.

The long-awaited and controversial Tarrawonga extension approval – which follows NSW government approval of the expansion project in January – did little to regain investor confidence with Whitehaven’s shares plunging 14c to $2.39.

Whitehaven and its 30% joint venture partner, Idemitsu, are seeking to expand the mine to the east and north, increase the production rate from 2 million tonnes per annum to 3Mtpa, and extend the project life from 2017 to 2030.