Good mine planning is vitally important to the design of mines, and even though mine design can proceed without it, mine planning adds most of the value.
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Quality planning leads to economic and practical stope extraction. While this is a misunderstood and diminishing practice, it is essential if a mining operation is to be viable. This article will look at the importance of stope design in mine planning and will explore current and future stope design methods for underground mining.
Key Aspects of Stope Design
Before drilling and extraction go ahead and time and money are invested, the key aspects of stope design must be properly considered by planning and production engineers. This is vital for good mine design.
Engineers must consider the stope geometry, including the mining dimensions and footwall angle, and ask questions such as whether the stope can be easily backfilled or could be bogged, and whether the physical constraints and parameters of the production drill allow drilling to commence.
Key aspects that govern optimal extraction must also be considered. These include the efficiency of bogging using manual or remote techniques, rise and stope location, the void ratio, extraction sequence, and blast sequence. Drilling and blasting parameters, stope optimization, including evaluation of the stope section, practical stope design, low-grade area, and the cut-off grade are part of a good stope design.
The capabilities of the equipment and the expertise of operators must be considered during stope design, along with financial factors such as capture costs. The engineers designing the stope must also communicate effectively with geologists, and it is important that geotechnical conditions are fully studied, analyzed, and planned for during the design process.
Rushing the planning process can lead to critical failures within underground mining, so it is crucial that engineers design elements such as stopes well and consider multiple aspects before operations begin. This will significantly improve the safety of workers and the economic viability of underground mining operations.
Importance of Stoping-Based Methods in Underground Mining
Stoping involves using pillars or artificial supports in mining operations, as opposed to unsupported methods.
Stoping has advantages for the mining industry by limiting the impact on the surface, which increases the sustainability of mines. Stoping-based methods cause very little subsidence and help with public perception of the mining industry. These methods are cost-effective and have already become a common feature of underground mines.
However, there are risks associated with increasingly complex rock geometry as mining operations exploit ever-deeper orebodies, creating potentially dangerous conditions for mine workers and equipment. For this reason, considering every parameter is important during mine planning.
Software-Based Optimization Strategies
Open-pit optimization has been available since the 1980s. Today, mining engineers utilize increasingly sophisticated software for design and planning.
Computer modeling offers engineers greater flexibility for optimizing stope design and selection. Enhancing underground mining operations is a complex procedure due to the variety of deposits, rock morphologies, mining methods, and mine access methods.
Multiple researchers have developed solutions for individual tasks in the mining design and planning processes, as well as for automating manual stope design. Opportunities for developing an integrated methodology and research software package have existed for decades, with recent research making a significant contribution to this area.
Several software packages have been developed over the past few decades, including multiple tools developed as part of the AMIRA research project. The goal of AMIRA is to create a commercially supported product that can be used widely in the mining industry.
The P1037/P1043 projects have developed optimization engines for each stage of planning and the strategy optimization toolchain. The optimization engines cover stope shapes and layout, development design, access, stope, the hill of value analysis, computing execution controllers and automated scenario generation, and the optimization of stop, development, and access sequence for the mine’s complete life cycle. A key feature of the project is a research user interface which can be replaced by a commercial user interface.
Surveying Current Developments and Identifying Future Opportunities
As the world moves into the 4th industrial revolution, the mining industry is taking advantage of advanced mathematical modeling, enhanced software capabilities, improved connectivity, Big Data paradigms, and vastly improved connectivity.
Using novel technologies, stope design is crucial for optimal mine planning and ensuring the sustainability of the industry. Recent developments have focused on stope optimization algorithms.
To investigate current development and future stope design perspectives, a team writing in Energies has performed an industry survey of mining engineers and professionals.
Out of 500 targeted industry professionals, 36 satisfactory results from 20 countries were received by the authors. In the survey, no dominance of a single stope design method was found, and even though numerical models have started to replace empirical methods, empirical methods and personal expertise are still widely used by engineers and mining industry professionals.
A total of 87% of respondents indicated a readiness for change in stope design practice. The most important improvement suggestions for stope design in the survey include:
- Gathering more geotechnical data
- Software development
- Integration into general mine planning
- Backfill predictability
Additionally, 45% of respondents have utilized rock mass and ore categorization investigations to improve stope design.
The study has identified that an iterative approach for stope design during multiple phases of mining operations has not been properly established and utilized. However, 69% of all responses have reported changes to the mining method and indicate that the industry is ready to implement new, more efficient stope design methods.
The authors behind the study conclude that if new stope design methods are to be properly implemented and the benefits demonstrated, case studies should play a central role.
References and Further Reading
Janiszewski, M, Pontow, S & Rinne, M (2022) Industry Survey on the Current State of Stope Design Methods in the Underground Mining Sector Energies 15(1) 240 [online] mdpi.com. Available at: https://www.mdpi.com/1996-1073/15/1/240
AMPS (2021) The Importance of Stope Planning Prior to Drill Design AMPS [online] advancedminingproduction.com. Available at: https://www.advancedminingproduction.com/2021/the-importance-stope-planning-prior-drill-design/
Alford, C & Hall, M (2014) Strategy Optimisation for Underground Mines alfordmingsystems.com [online] Available at: https://alfordminingsystems.com/wp-content/uploads/2014/12/Strategy_optimisation_for_underground_mines.pdf