The notion that hydropowered equipment uses or wastes more water than compressed-air (pneumatic) drilling or electric drilling is a misconception, says hydropowered equipment manufacturer Novatek MD Julian Wills.
“The reality is that all water is recovered, depending on the mines’ in-house circuitry, either as return water to the hydropower pumps or through the usual mine wastewater system. Some mines, especially deep-level mines, use a lot of cooling water, owing to operating conditions often being higher than 30 ºC. In this case, all rock drill exhaust water is used for cooling in the working areas.”
Wills adds that, even when a mine uses the water for cooling, water can be recovered and recirculated.
On shallower mines, a large amount of cooling water is not necessary, and those operations recirculate about 75% of water using hydropowered equipment, with the balance used for flushing the drill hole. This is legally required to suppress dust from the drilling, since dust poses many health risks when inhaled constantly.
“Considering that water drills penetrate at more than twice the speed of pneumatic or electric drills, their overall water use is actually lower,” mentions Wills.
Novatek offers water management advisory services in this regard and is often involved in the planning stages of projects that use hydropower, to help design systems to manage water use and wastewater, and control water so it does not mix with the surrounding reef. The company also advises on how to prevent water from penetrating orebodies, as platinum ore tends to absorb water if not managed effectively.
Wills highlights that more mines are considering hydropowered drilling, compared with pneumatic or electric drilling, owing to the increased efficiencies achieved. For example, Novatek works with a contract miner in the Impala Platinum group, which has been operating at a mine in Mpumalanga for 12 months and achieving results twice as productive as what a mine in the group achieved in similar geological areas using other equipment.
Owing to the face advance a month achieved using hydropowered drilling in the challenging area – a steeply dripping orebody at about 35º – Wills says an expansion of mining activities is under way that would not have been initiated had the contract miner not tested the hydropowered equipment.
Designed to Win
Novatek is developing a product that was, as a concept, entered into the Isidingo design challenge, called Isidingo DRILL, a competition hosted by the Mining Equipment Manufacturers of South Africa Association from mid-September to mid-October this year.
Novatek was one of three finalists, at Mining Weekly’s time of going to print.
The aim of the competition was to have manufacturers, engineers or students come up with drilling solutions that are better suited to mineworkers’ requirements, which is linked with drilling efficiency and often left unacknowledged by mines, says Wills.
The competition also sought to provide technological solutions for the problems that mineworkers encounter when drilling underground.
Criteria for rock-drill systems entered into the competition included that it weighs less than 16 kg, does not use compressed air as an energy source, allows for the parallel drilling of holes and has a setup and dismantling time of between 10 min and 15 min. It should also be easier to handle than existing rock drills.
“Although we work in drilling, the competition’s quantifying some of the equipment requirements posed a radical rethink and specific planning in terms of product development.
“The product is a complete reworking of our stope rig systems, coupled with our hydropowered rock drills. Two proven technologies have been reengineered to ensure lighter and more user-friendly drilling,” explains Wills.
Additionally, testing of the product has confirmed that it can reduce noise levels substantially, since hearing loss is a big issue underground, especially when pneumatic drills are used. This development can drop the noise by at least 6 A-weighted decibels.
Novatek is aiming to take the product to market in the first quarter of 2019, following prototype testing and trialling in the next few months.
Wills notes that Novatek has had to expand into other markets, such as automotive, oil and gas, petrochemicals, pulp and paper, and manufacturing, to make up for the shortfall of mining projects that would have been willing to take on trials of acquiring of hydropowered equipment.
“We have not given up on mining, but we want to create a baseline that does not depend only on mining.
“The industry is under a lot of cost pressure and is responding appropriately,” he adds, especially with platinum prices not being favourable and policy uncertainty weighing heavily on investment,” he explains.
Fortunately, the publishing of Mining Charter 111 has added a level of certainty, irrespective of whether the content has been received favourably, Wills points out.
He says it is stable and companies can respond to it.
Novatek is especially pleased with the increased local-content component in the charter, which requires mines to use more locally produced products and procure more local services.
Wills says this iteration of the charter definitely has a more prominent focus on socially and economically improving communities around mines, which is welcomed, but it is still too early to tell which elements of the charter will have positive and negative effects, especially with underlying factors still needing attention in the political environment.
“The changes in the charter are not sufficiently exciting to encourage international investors back,” he concludes.