Quebec explorer and developer Nippon Dragon Resources has announced that it is restarting development work at its Rocmec 1 gold property, which it will use as a showcase for thermal fragmentation technology.

The company will employ its patented mining method at Rocmec 1, as well as conventional mining methods as warranted.

The thermal fragmentation process for narrow vein mining involves drilling a series of 15 cm pilot holes into the vein with a conventional drill. Thermal fragmentation (thermal head, compressed air and water) is then inserted and spalls the rock, quickly increasing the diameter of the hole to 30 cm to 110 cm. After this, ore can be extracted in 0 mm to 13 mm fragments. The leftover rock between fragmented holes is then broken to recover the remaining ore.

Each work site is organised within two superimposed drift levels, about 20 m apart. By drifting directly into ore, mining waste and development costs are minimised, according to Nippon.

The company says that the use of soft explosive charges means that the hanging wall and footwall are left intact, with only the mineralised corridor itself extracted.

Nippon has submitted an updated reclamation plan for Rocmec 1 to the Quebec Ministry of Energy and Natural Resources, reflecting the progress of reclamation work that was conducted on the property in the past summer.

The underground development work will be conducted in phases, the first of which will focus on level 45, followed by Phase 2 focusing on level 90. The work is expected to extend over a 20-month period.

Development plans for subsequent phases are currently ongoing.

Rocmec 1 has a measured and indicated mineral resource of 570 300 t, grading 6.52 g/t gold (119 500 oz) and 1.51-million tonnes inferred at 7.4 g/t gold (359 600 oz).

Nippon, through its distributor MaXem, is continuing efforts to deploy the technology in South Africa’s mining industry. Gold major AngloGold Ashanti has conducted work with thermal fragmentation technology at an underground mine in the country.