Longevity of Current Mines (LoCM)
“More from the same, with the same”
One of the constraints to current conventional narrow reef underground gold and PGM mines is the lack of an accurate, faster, lighter and manoeuvrable drilling system that uses an alternative power source to compressed air. Three drilling technologies were identified that have the potential to improve on all the constraints that are offered by current drilling technologies: the VIBES Telescopic (GST) drilling machine, the CMTI MT 3500 multi-drilling machine, and the EPIROC drilling machine.
Underground trials were planned with researchers to monitor the drill machine performances. The team put together a report of a comparison of the performance analysis with the original equipment manufacturer (OEM) specifications. The team also updated the Technology Availability and Readiness Atlas (TARA) system and published a best practice document.
The CMT MT3500 drill machine was used to conduct an underground trial at Bathopele Mine. From the OEM report (CMTI, 2018), the underground test results of the CMTI drill machine achieved an average of 368 operating hours per month. The EPIROC drill machine has undergone underground testing at Anglo American, and a full report of the machine performance was presented to the Mandela Mining Precinct.
The drill machines of both VIBES and CMTI have the potential to meet industrial criteria, the first of which is to enable the operation of the drill out of the dangerous area. The underground application is dependent on the acceptance of the operators to operate the machine, and the ability to adopt the “modernised thinking” approach. The CMTI is further challenged with the mine design for accessing workings and the logistical environment to operate.
No substantial data could be obtained from any underground trails, which were monitored by the research team. The researchers could not get access to the sites when the underground trials were done; this was due to non-continuous underground testing being conducted at the Harmony Bambanani Mine, testing the VIBES (GST) drill machine.
This research was commissioned to the CSIR.
The Drilling Equipment Monitoring project has been completed. A surface test facility is being established to enable a standardised facility to test all the drill machine performances and compare the results, the data of which will be made available in the TARA system.
The Theory of Constraints (TOC) applies to the mining cycle and its activities for stoping and development. Research was directed towards a study using TOC to identify typical mining cycle constraints within current mining operations while developing a model (or manual) that can be used by mining companies to utilise the theory of constraints, in a consistent and meaningful way to optimise current mining operations.
The TOC improvement methodology implementation manual was validated in respect of a successful TOC ore flow implementation at the Lonmin, Rowland Shaft – a narrow reef platinum mine. The research team identified the process constraint(s) and determined the most effective method to exploit the process constraint(s). The next step involved mitigating the constraint and re-evaluating the process. Once this was completed, start-up training was made available to the Mandela Mining Precinct team and steering committee representatives. At the end of the process, the Rowland shaft project was validated, and the team produced a high-level case study.
The implementation criteria, such as the exploitation and subordination rules for each constraint in an ore flow line from different areas (e.g. half levels or levels or raise line blocks) can differ slightly to extensively due to geological, mining, logistical and beneficiation differences. Thus, sub-ordination criteria, buffers, measurements and tracking rules will differ from mine to mine and can even differ from one raise line block to the next; or from one half level to the next in the same mine. Sustaining the buffer and constraint measurements and management rules on a continuous basis are crucial for a sustained TOC improvement initiative.
For all practical reasons, a TOC improvement exercise is one of the very few methodologies that will guarantee a successful, sustainable and significant improvement. This is if the TOC programme implementation rules are applied and maintained correctly and strictly.
This research was commissioned to the CSIR and Exxpleo. The researchers involved in this project are Sibusiso Ngobese and PG Laurens.
The Theory of Constraints project has been completed. Final reports have been submitted and training manuals were compiled to prepare users to adapt the TOC system.
As part of the Longevity of Current Mines programme, energy usage in existing narrow reef underground gold and PGM mines was identified as a focus area, as it is a significant contributor to operational costs. The recent load shedding resulted from irregular electrical supply raised concerns for sustainable future supply, which necessitates the investigation into alternative energy sources. The purpose of this project is to identify cost-effective alternative and/or regenerative energy sources applicable to mining activities.
The research team conducted literature reviews and interviews with professional leaders in the industry as well as suppliers of Energy sources to obtain information and data that will enable representative comparisons of each milestone.
The main milestones are:
The outcome using the Levelised Cost of Electricity (LCOE) analysis shows that solar power and wind are currently the lowest regenerative sources of electricity but an integrated energy approach is required to fully utilise a sustainable energy source. It is further proposed that conceptual research and study work is required to investigate the integration of alternative and regenerative energy sources in more detail, in order to minimise energy costs for the mining sector. The availability of commercial equipment should be investigated to determine its application towards the implementation of an integrated mining energy system.
This research was commissioned to Impact Advantage.
This project is still in progress. A detailed Sector Coupling Model is to be developed from the study findings; it will guide the understanding of the coupling of electricity, heat/cooling and transport. Specialised tools (PLEXOS) will be utilised to model optimal investment opportunities.
Along with increased travelling times, additional work activities are required, such as safety meetings, ‘making safe’ procedures, and installing safety nets and roof bolts. As a result of the additional face activities taking place during the mining cycle, it does not support a daily conformant blast. It was realised that a lost blast analysis methodology needs to be investigated to enable an understanding of the root causes of non-conformant blast events.
The analysis was done through literature reviews of technologies for accurate recording of lost blast information and lost blast root cause (RCA) analysis methodologies, using data from Lonmin’s non-blast daily reports. Discussions were also conducted with original equipment manufacturers (OEMs) and the mines in order to gain a holistic understanding of the prevailing practices and technology in the industry. The team implemented project planning and initiation; they conducted literature reviews of local and international research relating to shift cycles in the mining industry; and drafted report findings.
Lonmin Platinum Mine provided reports on the throw blasting practices they captured and implemented on their down-dip mining operating shafts. Alternative methods were also analysed from work done at the mines, using breast mining. Further work was done for blast patterns and explosive types.
The practice of RCA in occupational health and safety (OHS) management in the mining industry is continuously improving. The use of RCA on lost blast incidents will empower the mines to address the actual root cause of an effect, resulting in step change improvements in productivity and OHS. The RCA guidance notes and lessons learned from RCA in OHS management can be used to develop mine-specific lost blast RCA guidelines.
The way forward is to apply a standardised lost blast analysis reporting system, which is completely independent of data capturing from production line supervisors, but there is a need to record data from real time monitoring and measuring devices; this would enhance the analytical process to address the real issues at hand and would result in effective conformant daily blasting.
This research was commissioned to the CSIR. The researcher involved in this project are Fleckson Mageregwede and Jodi Pelders.
The project Blasting project is completed.