The operator had received full certification after a September independent audit by M&S Insurance and Safety Consultants.

The CORESafety framework aims to achieve zero fatalities and a 50% reduction in injury rates within five years.

"Certification is the culmination of a multi-step, multi-year process that requires dedication at every level of an organisation - from the miner through management - and I commend Consol for prioritising the safety of its people through this significant commitment," NMA president and CEO Rich Nolan said.

"Safety is an area where complacency has no place and the CORESafety framework is an important tool to drive constant vigilance and awareness."

Consol president and CEO Jimmy Brock called the achievement a tremendous honour and a testament to the work and dedication of its miners.

"Safety is more than a core value at Consol… it is a condition of employment and a way of life," he added.

CORESafety is a risk-based mine safety and health management system developed by NMA that requires a commitment by participants to the system, and for them to implement a functionally equivalent version of the CORESafety safety and health management system.

Members must also submit to annual self-assessments of progress toward implementation of the CORESafety safety and health management system to the NMA. Should a company elect to achieve or maintain its CORESafety certification, it must complete a thorough third-party assessment of its safety and health management system to verify that it is functionally equivalent to CORESafety and submit the assessment report to NMA.

Consol owns and operates the Pennsylvania Mining Complex, the Baltimore Marine Terminal, and controls over 1 billion short tons (907Mt) of undeveloped reserves.