Although local manufacturer of water-powered rock drills and drilling equipment Novatek has registered consistent hydropower equipment sales to long-standing customers, such as large and deep-level mines, the company has recorded steady growth over the last 18 months in the sales of hydropowered equipment to new mining operations aiming to reduce electrical power consumption.

The company primarily specialises in the manufacture and supply of hydropower systems for underground hard-rock mines in South Africa.

Novatek MD Julian Wills tells Mining Weekly that the 100% South African-owned company manufactures all its equipment in-house at its factory in Robertsham, Johannesburg. He believes that it is an important factor in the company’s continuing to receive strong support from local mining operations.

The company was recently awarded a contract to supply junior platinum miner Atlatsa Resources' Bokoni mine’s Brakfontein shaft, in Limpopo, with its centralised pumps and dedicated piping systems to develop new raise lines using water rock-drilling technology.

According to Atlatsa's website, Bokoni mines about 80 000 t/m at an average grade of 4.3 g/t. This production comprises the Merensky and upper group two reefs at 50 000 t/m and 30 000 t/m respectively, and once processed, it produces approximately 150 000 oz/y of gold, platinum, rhodium and palladium.

Wills says that Bokoni plans to roll out hydropower in 2014 to complete the production of its Brakfontein shaft raise lines.

“A centralised pumpstation, comprising several pumps with a common control system, will supply high-pressure water to power all mining tools in the stoping raise line, including rock drills and bolters, hole cleaners and saws,” he points out, adding that the excess water from the rock drills will be recirculated to significantly reduce overall water use and dirty-water pumping.

Since late 2012, the company has been supplying several of its microhydropower range of drills to gold major AngloGold Ashanti’s Mponeng mine, near Carletonville, through the mine’s primary contractor, which manufactures and distributes high-pressure equipment High Pressure Systems (HPS).

According to AngloGold Ashanti’s website, Mponeng is mining gold at an average of 2 800 m below ground from the Ventersdorp contact reef and will soon mine even deeper on the Carbon Leader reef.

“The microhydropower drills range is an example of hydropower technology in its smallest form and is used with portable HPS pumps that power a single drill. The drills can be used in applications ranging from roof bolting and support drilling to development and production drilling, which are mainly hand-held applications,” he says.

Further, Wills notes that Novatek has been supplying manganese ore and alloy company Assmang’s Dwarsrivier chrome mine with localised pump sets since mid-2011. The pump sets can power up to two rock drills.

The mine is situated on the Dwarsrivier farm, about 30 km from Steelpoort and 60 km from Lydenburg, in Mpumalanga.

“The pump sets and rock drills are being used for development and production at the mine’s new Northern shaft,” he adds.

He highlights that Novatek has been supplying ASX- and JSE-listed gold miner Gold One’s Modder East gold mine, 30 km outside Johannesburg, on the East Rand, with localised hydropower systems since 2009.

Wills states that Novatek’s hydropowered hand-held drills are responsible for all reef production at the mine and are powered by localised reticulation systems, each supplied by its own central pumpstation.

He adds that there are several smaller projects and trials being undertaken by other mining groups, as well as some longer-term projects on new mines, over which Novatek is holding discussions about the possibility of supplying hydropowered equipment for use in their operations.

Hydropower Functionalities and Advantages

Wills tells Mining Weekly that hydropowered mining systems typically operate at pressures of between 12 MPa and 18 MPa. Clear water is used and it can either be exhausted in the working areas where it provides localised cooling or returned to the pumpstations in separate pipes.

“Water obviously has almost no lubricating properties and does not inhibit rust. Consequently, the equipment is made of stainless steel and engineering-grade polymers are used for seals and bearings,” he notes.

“On new mines, often the power required to mine with compressed air is simply not available – at any price – owing to State-owned power utility Eskom’s limited capacity. However, using hydropowered systems can significantly mitigate mines’ power requirements, thus ensuring, in most cases, that their operations will not be interrupted, owing to power constraints,” Wills explains.

He highlights that hydropower technology can reduce power consumption by between 90% to 95% compared with existing compressed-air systems.

“In ageing networks, compressors routinely operate excessively to cater for air losses. However, hydropower systems allow for significant increases in productivity,” Wills highlights.

Moreover, he notes the other advantageous aspects of water rock-drilling systems – they are more than 50% faster than standard pneumatic drills, the water jet cleaning application reduces rock-face cleaning time, and face scrapers can be eliminated for short panels with adequate dip levels.

Consequently, safety and health issues are dealt with through reducing exposure times to rockfall hazards. Improved cooling, visibility and noise reduction can also be achieved.

Wills states that the capital cost of hydropowered equipment is on average about 60% less than that of an equivalent pneumatic powered system, while hydropower operating costs can be reduced by up to 40%.

Dealing with Challenges

“Compressed-air mining systems have long been the entrenched norm for mining operations and new technologies, such as hydropower, require mine managers to change their thinking patterns and ways of operating to recognise the benefits of such systems,” states Wills.

He says the perceived threat to jobs, owing to the productivity advantages made possible by hydropowered mining, has been a bone of contention for some trade unions.

“However, the reality is that additional staff are required in the mine to support the additional hydropower infrastructure and to clean the extra production materials,” he states.

“Management has to explain clearly to workers that, through the correct use of hydropower, the number of personnel in the working areas can be reduced, which is the highest-risk area. The challenge is that most mines are still reluctant to meaningfully engage the trade unions and commit to partnering in making technological changes successful,” he laments.

Wills points out that several mining groups have embarked on sophisticated mechanised mining strategies such as trackless systems.

“These are large leaps - technologically and organizationally. To switch from labour-intensive mining operations to trackless systems requires a much higher level of overall skill for success,” he states.

Further, Wills notes that there have been numerous implementation failures on mines that have not been able to make this leap, owing to the lack of proper planning or technical expertise.

“We believe that hydropower systems and the optional use of other appropriate related technologies, suit most South African hard-rock orebodies, as they are simple to implement and allow for the incremental upskilling of workers.”

Novatek provides a range of services to make the implementation process easy for mines, says Wills, adding that the company provides design input for feasibility and mine-planning studies.

Novatek also supplies turnkey installations, training and project implementation management and on-site maintenance of the equipment.

VIDEO:
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