ASX-listed Paringa Resources has achieved record productivity rates at its Poplar Grove mine, in western Kentucky, where underground activities are undertaken by the first mining unit (Unit 1), comprising two continuous mining machines (CMs).

During the week of June 10, the company achieved a peak mining rate of 306 ft of material being cut in a shift, equalling a 100% increase on the week before.

Unit 1 has now completed the majority of bottom development, with construction of the ventilation overcasts being the only remaining project, which is expected to be commissioned in the coming weeks, Paringa said in a statement on Tuesday.

Commissioning of the overcasts would allow the mining unit to be ventilated in a manner known as “split ventilation”, which would allow both CMs to operate concurrently, further boosting productivity.

Paringa reported that softer-than-expected cutting conditions were leading to reduced consumption of bits for the CMs and roof bolters, as well as allowing the use of less expensive bits. The estimated costs savings were about $1.5-million a year, when compared with the bankable feasibility forecast.

All underground and surface mobile equipment necessary for the operation of two mining units was on site, and Paringa said it was in the process of hiring hourly employees in anticipation of commissioning Unit 2 over the coming months.

Paringa would also seek approval from the Mine Safety and Health Administration (MSHA) for an extended cut plan, with the potential for cut depths to be significantly increased from the current 20 ft limit.

This approval, coupled with split ventilation, would enable another major step-change in mining productivity, Paringa said, adding that all other surrounding mines in the region had received MSHA extended cut approval, with customary approval limits of up to 40 ft.

The recent increase in productivity is largely attributable to mining operations having progressed beyond the challenging conditions caused by a paleochannel intersecting the mine workings.

Paringa further stated that it remained on track to achieve steady-state productivity rates of 560 ft/shift for Unit 1 and Unit 2 operations before year end 2019, equating to the production of 1.8-million tonnes a year of saleable product on an annualized run-rate basis.

The coal handling and preparation plant and other surface infrastructure were functioning well, Paringa said, with plant yield increasing as out-of-seam dilution decreases.

Dilution during commissioning was largely attributable to underground construction activities, with additional waste rock mined in order to create space for underground infrastructure.