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South Africa’s mining industry needs to change its current mining strategy if it is to prolong its sustainability and retain the hundreds of thousands of jobs it supports.

This is the view of Mandela Mining Precinct programme manager MARTIN PRETORIUS, who heads up the Longevity of Current Mines (LoCM) programme.

The programme is aimed at improving mining practices and procedures particularly for established platinum and gold mines, already constrained by their current infrastructure, CHANTELLE KOTZE reports.

This article first appeared in Mining Review Africa Issue 1, 2020

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The LoCM programme is geared towards identifying gaps in the mining cycle to ensure that the country’s remaining deep-level gold and platinum mining operations are mined adequately and to their full potential, as cost effectively and safely as possible.

The programme will do so by using more efficient systems within the mining cycle to improve occupational health and safety performance, increase the efficiency of extraction and reduce costs.

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If a change in approach is not prioritised, it is estimated that the country’s gold and platinum-group metal reserves will be depleted by 2030 and 2035 respectively, placing 200 000 direct jobs (which supports up to two million dependents) at risk if the country is unable to find a way to sustainably and cost-effectively access and process its deep-level complex ore bodies productively and profitably.

This will result in a significant negative impact on the South African economy and a failure to maximise the extraction of the country’s abundant mineral wealth in the long-term.

The LoCM programme is one of six focus areas being pursued by the Mandela Mining Precinct via three work streams and three cross-cutting initiatives to extend the lives of mining operations constrained by current commodity price levels and rising costs.

The LoCM programme will work towards extending the remaining life of platinum and gold operations in the short term as these two sectors are nearing the end of their productive lives, a consequence of difficult-to-reach ore bodies or ore bodies that have become too costly to mine. Both of these aspects affect the continuity and sustainability of current mines.

“The work will entail processes of documenting and analysing the challenges and issues within the mining cycle experienced by mining companies of this description, within the gold and platinum sectors,” explains Pretorius, adding that the programme will work towards optimising the existing work process within the mining cycle.

For example, a normal gold or platinum mining cycle takes ten and a half hours to complete and is constrained by the current 8 hour and 20 minute shift durations (including the time it takes to travel to the working area) which results in a bottleneck in terms of time on face. This would either require one crew to work at multiple faces as a means to improve flexibility or instead speed up the production cycle.

The programme aims to analyse each of the critical activities within a mining cycle with the objective of achieving a specific outcome from each of the below:

  • Drilling: With the outcome of establishing a new and innovative drill rig with an alternative power source
  • Blasting: Looking at lost blast analysis reporting systems and throw blasting as an means to reduce face cleaning
  • Support: Introducing pipe stick support manufactured from waste material as a means to replace timber support
  • Shift cycles: A literature review on the impact of fatigue on production and fatigue management as well as the development of a blueprint to guide the review of shift cycles.

Most of these programmes were completed during the 2018/19 budget period with only three programmes running into the 2019/20 budget period, these include the drilling (completed in December 2019), support (to be completed by March 2020) and shift cycle (to be completed by February 2020).

While the LoCM programme has a short term horizon focused on addressing the challenges faced in conventional underground mines, the programme will transition into a longer term plan that will investigate how to begin introducing automation into these conventional operations, enabling them to be better prepared for the future.

Achieving the first LOCM outcome with the Isidingo Drill Design Challenge

The open innovation Isidingo Drill Design Challenge launched in 2018 and spearheaded by the Mandela Mining Precinct has culminated in the development of two new rock drill prototypes developed by local innovators to enhance current underground drilling operations.

Aimed at developing a new and innovative rock drill to be used in South Africa’s gold and platinum deep-level mines based on the industry’s need to be lighter, more energy efficient, quieter and easier to assemble and dismantle than the current drill rigs in operation, the Isidingo Drill Design Challenge encouraged the rapid design and prototyping of rock drill concepts.

Current drilling technology is not energy efficient, as well as being heavy, noisy and prone to extreme vibration which results in fatigue, noise induced hearing loss and white knuckle syndrome.

In addition, the conventional configuration means that operators are exposed to the most dangerous conditions of the mine, including fall of ground, seismicity, and gas blows.

In an attempt to improve the operational cost, as well as the health and safety of rock drill operators, parties interested in participating in the challenge were asked to submit a concept design based on four key criteria, namely:

  • The weight of the drill must be less than 16 kg, as opposed to the current drill weight of between 28 and 32 kg;
  • The drill must use an alternate power source to compressed air;
  • The drill design must incorporate parallelism; and
  • The drill must be able to be set-up and taken down within 10 – 15 minutes.

Six secondary criteria to be considered with the design of the drill is that it must produce more thrust than current drills, must be designed to operate quietly to be able to render noise levels that are less than 95 dB, must reduce vibrations for the operator, must improve on current drilling speeds or penetration rates, must be easily operable by a rock drill operator, and must be human-centred in its design.

The two prototype rock drills, which are a significant step towards modernising the way drilling is undertaken in South Africa’s difficult to access narrow-reef underground gold and platinum mines, are set to reduce the exposure of operators to dangerous conditions and contribute to the aim of zero harm in mines.

The challenge was divided into three phases. The first phase entailed the introduction of a new and innovative rock-drill concept design; followed by the prototype construction associated with testing and monitoring. The third phase, to be undertaken during 2020, will entail manufacturing and underground performance testing and adjustments to the current design (expected to be completed in March 2020), which will culminate the development of the two prototypes as commercial drill rigs.

After a rigorous evaluation process, two local companies, namely Novatek and HPE, were selected to develop prototypes, which were tested at the Mandela Mining Precinct.

“The tests successfully illustrated both company’s adherence to the primary criteria of enhancing the performance of the drill, reducing the exposure of operators to dangerous conditions and contributing to zero harm.

HPE presented a versatile drilling system. “With our new offering, drilling is now possible in three ways, with a novel hole guide puller, a stope drill jig, or in a conventional manner with a thrust leg,” says HPE director Ulrich Kienle, adding that its drilling system is suitable for any angle and application. “Once the first hole has been drilled, the hole guide puller repeats the process and guarantees correct burden spacing, parallelism and in-line thrusting.”

Dubbed the Buffalo, Novatek’s drill incorporates a spring, shaped like a buffalo horn, which embodies its strength, accuracy and speed. “What we delivered meets some of the criteria really well. In our early tests, we encountered improvement on the noise levels, which we were not able to replicate, but we are eager to continue working thereon for the third phase,” says Novatek MD Julian Wills.

Shift cycle blueprint – a game changer for the industry

The investigation of alternative shift cycles for different operations, also a significant research programme within the LoCM programme, will focus on how to improve on the key elements within a shift cycle, explains Pretorius, with the objective of incorporating all of these key elements in establishing a framework, or blueprint for the development of new optimised shift cycles going forward.

This shift cycle framework will be informed by the outcomes and learnings of the drilling, blasting and support activity programmes still underway within the LoCM programme, which will be finalised by February 2020.

“We will be inviting all stakeholders to join in on the finalisation of this process. Because we are moving this from a technical study to an implementable blueprint, we will be finalising this framework through the Successful Application of Technologies Centred Around People, or SATCAP programme, whose aim is to enable and sustain healthy and robust relationships trough the hosting of workshops for all stakeholders,” Pretorius concludes.