The company said this record is higher than any Mastermyne and Whitehaven development production record and is amongst the best records for cut and flit panels in Australia.
"These results at Narrabri will go a long way to securing Mastermyne's reputation as a supplier of choice as a cut and flit development driveage specialist," the company said.
The team also reported a record bolted rate of 506m and record best shift of 65m.
The scope of Mastermyne's $33 million Narrabri cut and flit contract includes the full management and supply of equipment and skilled personnel to execute the works.
The project employs approximately 55 full time personnel and expected to finish in May 2019.
Mastermyne is deploying a continuous miner and ancillary development equipment from its fleet for the project.
The formation of MG201 and MG202 gateroads at Narrabri, face and bleeder headings, and associated roadways will total 2,222m.