Energy Reduction

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Theme Leaders: Michelle Levesque

The 40% Mine; Improve the energy consumption profile of deep mines

The Challenge: The 40% Mine is an initiative that aims to reduce the energy consumed by mines to 40% of their current consumption levels by 2040. This theme of the UDMN will work toward this goal specifically for Ultra Deep Mines.

The energy required to power underground mine operations is extensive and can be equivalent to that used for a small city of a few thousand people. For the average Canadian underground hard rock mine, the energy input costs to production alone are 18%. This fraction has been steadily increasing for the last 50 years and this trend continues. For underground mines in soft rock the average is closer to 22%. According to some empirical models for all fuels energy consumption (electricity, heating, cooling, transport fuel) 97% of the variance in the models can be explained with just three variables: i) production rate, ii) heating degree days and iii) production depth. Proposals in the following areas will be particularly welcomed, but this theme of the UDMN aims to support research, development and innovation/commercialization activity in the field of energy that focuses on, or specifically relies upon, ‘extreme-z’.

• Innovation arising from enhanced understanding of the psychology of energy consumption in all types of stakeholders in ultra deep mines. Such works should be commercializable and may rely on behaviour change mechanisms.

• Measurement, Auditing, Benchmarking and Optimization of energy systems for ultra deep mines. Innovations are particularly welcome in the fields of energy measurement systems, audit methodologies and consumption metrics, realized in hardware, firmware or software that specifically address the needs of ultra deep mines. This includes application to potentially non-obvious energy flows in the sub-surface, including thermofluid distribution such as ventilation air flows, and power transmission such as compressed air distribution.

• Alternatives to diesel powered loading and haulage systems that offer substantial cost savings or operational benefits relative to conventional practice for ultra deep mines.

• Deep mine cooling technologies that will deliver a discounted cost of a MWhr that is at most 50% of that of a conventional vapour compression refrigeration solution.

• Development of vertical transportation of ore and waste with an energy efficiency of greater than 66% relative to the potential energy of raising that mass to the surface from depth an ultra deep mine.

• Energy storage technology and development in or for ultra deep mines. This could include (flow) battery technology, pump storage (including the deferral of ore and waste rock haulage), liquefaction of gases, safe installation of flywheels, supercapacitors and superconductors, and Compressed Air Energy Storage systems.

Projects:

1. Towards Freezing-on-Demand with Closed Loop Geothermal Systems (McGill University)

The research program principally comprises in situ performance assessment of an industrial scale geothermal heating system already deployed in an operating mine to better understand extraction and use of renewable geothermal energy.

2. Improved Thermal Mass Utilization Decreasing Applied Ventilation System Energy Intensity (MIRARCO)

To defer the installation of a mechanical refrigeration system for the cooling of intake air in one of Canada’s ultra-deep mines specifically by examining the socalled Natural Heat Exchange Area (NHEA) of the mine to determine how additional refrigeration capacity may be gained, through re-engineering of the NHEA.

3. Determination of the Acceptable Geothermal Resource for Open Loop Systems (McGill University)

This project will undertake a practical determination of the performance of an open loop geothermal system installed in a working Canadian mine. The work aims to identify the optimum technique for using this geothermal energy in mining infrastructure and/or mineral processing operations to reduce cost.

4. Wind2Ice: Low Cost, Low Carbon Creation of Ice to Cool Deep Canadian Mines (MIRARCO)

The work program aims to prove the technical feasibility of alternative refrigeration systems that have the potential to deliver zero marginal costs of cooling for ultra-deep mines. It will consider 2 ways in which ice can be manufactured for ultra-deep mine cooling. The first will consider the mine air heating system at Stobie Mine in a re-engineered mode to provide not only summer, but year round refrigeration effect. The second element will be to investigate driving the compressor in a conventional refrigeration cycle with shaft work from a wind turbine.

5. Electric Mining Machine for Personnel Transport (Tracks & Wheels)

Create a fully functional electric utility vehicle to be used for ultra-deep mining.

6. Battery-Powered Underground Utility Vehicles, 150-250hp (FVT Research Inc.)

This project will create an industry-first high-power battery-electric drive system suitable for mining production equipment up to 250 hp.

7. The Cryofan© Project for Ultra Deep Mine Chilling. (CanMIND Associates)

The business case supporting the use cryogen based chilling systems in ultra-deep mines relates to the well-known effect of auto-compression, the increase in the temperature of the ventilation air as it descends due to the adiabatic lapse rate, which requires a significant amount of infrastructure, chilling plants, piping and pumping to create the subsurface environment that meets the needs of the workers. In addition, cryogenic energy storage and the specific applications to mining such as the production of compressed air or electricity and zero emission vehicles serves to extend the influence of cryogenics to a broader spectrum of mine services providing economies of scale.

This project represents the initial critical introduction of cryogenic technology to the mining industry for an application relevant to the industry and attainable given the existing state of maturity of the engineering in the cryogenics industry. The global demand for mine chilling will increase as deeper mines are built to meet the demand for resources, more mine development occurs in hot climates and global climate change extends the length of the summer seasons in temperate climate zones. The cryogen, liquid air or nitrogen can be economically produced and has other significant uses in the mining environment such as energy storage, which suggests that this technology may be competitive with existing technologies.deepmining