Seismic Risk Management Plan
The WA DMIRS have recently released a new Code of Practice document covering ground control for Western Australian mining operations. The new code of practice follows a risk-based approach, which means that the document does not advise on specific guidelines, but rather proposes a broad methodology for mines. Different mines require varying levels of detail which should be managed by the mine itself through assigned roles and responsibilities. For a full version of the document visit: https://www.dmp.wa.gov.au/Documents/Safety/MSH_CoP_GroundControl.pdf
The occurrence of damaging seismic events has a large impact on the risk profile of deeper mines. In my experience on deep level mines where seismicity has been a major risk, I know how overwhelming the occurrence of large events can be without the necessary knowledge, support and experience. I know the value of a well written, detailed and site-specific SRMP as it will ensure all staff members involved with excavation stability are made fully aware of the lessons learned, and that the knowledge gained from previous activities is sufficiently captured.
There are several papers and documents available to the mining industry on SRMP methodology. These documents are broad-based, due to the differences in legislation between countries and states.
Below is a plan layout which is based on the recently published paper by Potvin et al. (2019). In this paper, they developed a roadmap for a Generic Seismic Risk Management Plan.
DATA COLLECTION
Data collection describes all the data and monitoring programs the mine specifically has in place to monitor seismicity. This includes the geological model, mining-related parameters, geotechnical values, and the seismic system. In the SRMP the precise details of these data collection programs must be clear. Details should include:
Data project details (e.g. number of sensors, magnitude ranges, location accuracy etc)
System maintenance plans
QA/QC checks
From Potvin et al. (2019)
SEISMIC RESPONSE TO MINING
Once the relevant monitoring systems are in place, the effective analysis of data is the next consideration. All the analysis techniques here aim to understand and quantify the seismic hazard. The ability to know where the high seismic hazard areas are, and what drives those hazards (pillars, structure etc) is important. This is typically done through statistical hazard techniques, forensic investigations and numerical modelling. Any findings made through these techniques must be clearly stated in the SRMP.
From Potvin et al. (2019)
CONTROL MEASURES
Control measures describe all the actions that you as an engineer can use to mitigate the seismic risk. Some of these measures (e.g. changing the mining method) are more difficult to implement than others. In this section, it is important to ensure the document is simple but detailed enough that the controls can be understood and implemented by non-engineering personnel.
From Potvin et al. (2019)
SEISMIC RISK ASSESSMENT
The final component of this plan is describing the seismic risk. This is a vital part of the process, as it creates a feedback loop, which ensures that the effectiveness of the control measures can be tested, as well as ensuring the continual improvement of this process.
From Potvin et al. (2019)
GENERAL TIPS
The document should be thorough without being overly complex.
Should be understood by both underground crew and managers.
This document will make out part of the GCMP and therefore is admissible in court.
Ensure all responsibilities and tasks are clearly stated and communicated.
Be careful to only document controls which can actually be achieved, and not controls which are desirable but not achievable.
Hazardous does not mean dangerous. With the right controls, hazards can be managed.
This article is based on the following documents:
Generic Seismic Risk Management Plan for Underground Hardrock Mines
Code of Practice: Ground control for Western Australian mining operations
Still not sure about the quality of your SRMP document? Feel free to contact us and we can help you write up your SRMP document or carry out an audit.