Major Drilling says it is nearing the completion of a cave tracking system installation at the Turquoise Hill Resources and Mongolia government-owned Oyu Tolgoi copper-gold mine, in Mongolia.

In early 2000, Major Drilling established a drilling campaign in the middle of the Gobi Desert, with operational supplies needing to ramp up to support 20 rigs that were transported to the site.

This drilling work has since evolved into the tracking system that has proven successful in the block cave operation.

These trackers are lowered through a specially-drilled borehole into the Oyu Tolgoi orebody below. Block cave magnetic beacons are embedded into the orebody and spun to create a magnetic field.

“Magnetisation has been found to be the most effective way to track the fragmentation as an orebody caves in allowing loaders to mine the ore from draw points deep underground,” Major Drilling said.

Major Drilling’s teams strategically place magnetic beacons throughout the mine to create a 3D map and to track the position of the orebody cave-in flow. The cables are attached to the duct rodder, which is lowered from a winch system. Once the trackers are placed, block caving techniques will undercut and fragment the deepest points of the geology, according to the company. The orebody is then collected and taken away for processing.

“Block caving is a low-cost mining method used for the development of massive ore deposits,” Major Drilling says. “Mine planners often use an experienced specialised drilling company to precondition the block cave mining area through hydrofracking. Tracking the flow of the fragmented, caved ore is a critical part of accessing targeted orebodies.”

Mine planners use the information from the magnetic tracking devices placed by the Major Drilling team to understand the direction of intended failure the stone is moving.

Shaun Hogan, Major Drilling’s Project Manager at Oyu Tolgoi, said: “We are nearing the completion of the cave tracking system installation at Oyu Tolgoi. Over the past two years, we have worked very closely with our client and various stakeholders; this partnership has achieved a successful deep tracking network.”

In addition to block cave tracking, Major Drilling also performs seismic monitoring to help predict rock mass instabilities. Seismic monitoring is another specialised drilling service that makes large-scale block cave work safer and more productive.

Major Drilling was awarded the Rio Tinto Growth & Innovation Group Award for the successful seismic drilling program at Oyu Tolgoi in 2017.