Rock Stress Risk Reduction

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Resource extraction in Canada is occurring at ever greater depths and geotechnical risks are increasing significantly, particularly as they relate to stress within the rockmass. The challenges associated with this, in both the mining and oil and gas sectors, need to be addressed as failing to do so will foster unacceptable project risks. This in turn will impact investment and will jeopardize Canada’s competitiveness.

a) Induced Seismic Hazard Mitigation in Ultra-Deep Mines

The Challenge: Rock stress and stress-change management when mining at depth are absolutely critical to minimize geomechanics-related risks which can impact operational productivity, cost management and safety. Further, when rock stress-related ground failures occur, entire sections of mines can become inaccessible, with serious negative economic impacts and potential mine closures due to sterilization of ore reserves. Mine sequencing and de-stress blasting are currently used to modify the stress field and reduce the seismic hazard in deep mines but these techniques are often insufficient to adequately reduce rockburst potential and related risks in mines—in particular near vulnerable underground excavations. Thus, further complementary and innovative R&D methods are required.

Projects in this theme that will explore ways to better measure, anticipate, mitigate and manage and even modify built up stresses in the rockmass, resulting in more intelligent rock mechanics design protocols and advanced approaches (in part built upon experience from the Oil & Gas sector).

b) Extraction of Oil & Gas in tight shale rock at depth in non-conventional Hydrocarbon Reservoirs

The Challenge: The ability of the Oil & Gas (O&G) industry to extract hydrocarbons from tight shale rock deposits at extreme depth can be improved through cross-sectoral R&D involving Canada’s deep mining industry. Techniques applied to lower rock-related stress in underground mines are strongly applicable to the O&G industry and both sectors have a need to generate closely spaced fracture networks— for hydrocarbon release and transportation in the case of the O&G sector and caving/fragmentation/stress management purposes in the case of the deep mining industry.

Despite the vast inventory of microseismic information that has been collected and interpreted by the O&G sector to understand fracture and reservoir stimulation (including information on the orientation, density and half-lengths of fractures), stimulated rock volumes are often poorly understood and can be difficult to reconcile with ultimate hydrocarbon production output. Difficulties are encountered in relating the stimulated volumes to the “geophysical observables”. Understanding these parameters is extremely important to ensure efficient and effective exploitation of trapped reserves.

Cross-sectoral R&D proposals will look at ways to make mines safer by reducing geotechnical risks through a broader understanding of these same parameters while also helping to ensure Canada’s ability to supply hydrocarbon-based energy resources into the future.

Projects in this theme will provide the underpinning of technology development and new knowledge to aid in tackling what are anticipated to become two of the more significant technical challenges for the O&G and ultra-deep mining sectors in the next ten years.

Projects:

1. Seismic Stress Inversion (ESG Solutions)

Apply newly developed method for stress tensor (direction and stress magnitude ratio) determination from microseismic source mechanism results thereby leading to advanced analysis and interpretive capability, which makes deep mines safer and more productive.

2. Development of a Numerical Model to Stimulate De-stress Blasting as a Stress Modification Technique for Deep Mining (Itasca Consulting)

Build tools that will enable industry to develop a better approach to designing a de-stress blast thereby dealing more effectively with the de-stabilizing effects of stress build up around its underground excavations.

3. Open Geotechnical Data Network & Data Analysis (Symboticware)

To use appropriately equipped mobile equipment to transfer data from ultra-deep geotechnical networks into a centralized data handling system and thereby enable real-time decision-making.

4. 4D Real Time Geotechnical Hazard Assessment and Reporting for Ultra-Deep Mining (Mira Geoscience)

To research, develop and implement a system for 4D (3D space and time) real-time geotechnical hazard assessment and reporting for ultra-deep mining.

5. Pillar Strength in Deep Mines – Measurement while Drilling – Direct Observation (Objectivity)

To determine whether Measurement While Drilling (MWD) jumbo drill technology is a useable tool in deep mines for determining the integrity of loaded rock pillars.

6. Hydraulic Pre-Conditioning of Highly Stressed Rock Masses (MIRARCO)

Develop an alternative methodology for safe stress management at ultra-depth.

7. Active Seismic Monitoring for Seismic Risk Reduction (Institute of Mine Seismology)

Turn sensitive velocity measurements from an active seismic source into in-situ measurement of stress changes in a volume of rock