The company said continued productivity gains achieved in the Hunter Valley and thermal coal production from a processing plant by-product stream at Hail Creek in Queensland were major contributors to the increase to 5.8 million tonnes for the quarter.

The NSW government said it was considering the implications of a Court of Appeal decision on Rio’s Warkworth project application.

“The mining sector told us that recent court decisions, including the Land and Environment Court decision, had created uncertainty,” NSW Planning and Infrastructure Minister Brad Hazzard said.

“The government joined in the appeal on procedural grounds.”

“In NSW all major mining projects are comprehensively assessed on their merits with extensive consultation with the community and other government agencies.

“Major mining developments in NSW are determined at arm’s length of government by the independent Planning Assessment Commission.”

NSW Resources and Energy Minister Anthony Roberts said mining supported thousands of families across the state.

“The mining sector provides career opportunities – often in regional areas where job prospects are limited,” Roberts said.

Turning to Rio’s hard coking coal production, the company reported an 18% higher result than the first quarter of 2013 due to improved production from its newly expanded Kestrel mine in Queensland.

The Kestrel mine coal handling preparation plant was shut for upgrade works in the first quarter of 2013 as part of the Kestrel mine extension that was completed during the second half of last year.

Hard coking coal production was 20% lower than in the fourth quarter due to higher rainfall, in keeping with seasonal trends.

Total hard coking coal production for the quarter came in at 1.8Mt.

Semi-soft coking coal production was 10% lower than the first quarter of 2013, largely due to a planned change in the production profile.

The company continues to be plagued by its underperforming investment in Mozambique.

First quarter production in Mozambique was affected by rail and port constraints, as well as operational changes in response to security considerations.

Operations have been moved to a day shift only and were suspended for a period in February 2014.