Energy-smart mining

A new trend in mining management offers a foundation for effective energy-related decision-making, and could create a pool of knowledge that will influence the design of future mines. It’s called an “all fuels” baseline energy audit, and pioneering work towards its development is now being done in B.C.

“A baseline audit is the first step in an energy management process. You review the historical patterns of energy use, then study the energy balances for all processes and facilities and all energy types,” says Markus Zeller, Industrial Technology Innovation Manager for BC Hydro, which has supported the development of the B.C. baseline protocol. “By breaking it down by process area, you don’t just see the energy performance of your plant as a whole; you can pinpoint certain areas where there might be opportunities for energy improvement.”

The baselining process — well established in the pulp and paper industry but relatively new to mining — identifies specific process areas at an operation, such as blasting, transport, grinding, or concentration. Then it assesses both total energy use and energy intensity (the amount of energy used per unit of production) in each area. By drawing clear boundaries around process areas, a detailed energy snapshot of the operation rapidly emerges. Applying the same standardized process in later years, or at other facilities, allows comparisons of energy consumption and efficiency, at one operation, or across different operations, that have not been possible up to now.

“Baselining is a protocol, a consistent, objective way of measuring where energy is consumed,” says Steve Quon, BC Hydro’s Marketing Manager for the mining sector. “It doesn’t matter if it’s a coal, copper, or gold mine, open pit or underground, located in northern B.C., Ontario or Chile. If you know where energy is being consumed, you can think about where you might be able to save.” Quon points out that the B.C. audit provides a comprehensive energy efficiency picture because it assesses the energy used from all sources, including electricity, fossil fuels, and explosives. The protocol also considers energy generated or recovered inside the mine boundary.

This summer, the newly developed B.C. baseline energy audit protocol was tested at Western Coal’s Wolverine open pit coal mine in northeastern B.C. The protocol was developed through a partnership between BC Hydro and BC Mining Research Ltd. (BCMR), an offshoot of the Institute of Mining Engineering at the University of B.C.

BCMR Principal Dr. Andrew Bamber says the protocol was designed in part to help B.C. mines respond to the national initiative “Towards Sustainable Mining” (TSM). Initially developed by the Mining Association of Canada to encourage responsible practices and build public trust, TSM’s terms of reference have steadily expanded.

Says Dr. Bamber, “The requirement to at least get a baseline for energy use and greenhouse gas emissions, coming from the national body of mining, has been adopted by the Mining Association of B.C. So we’re looking at how to implement it in a way that’s appropriate, useful and beneficial to the member mines of B.C. Just knowing where you are on the energy efficiency curve is the first step to moving down that curve.”

* Information for the article provided by BC Hydro.

Trends such as TSM are the key reason Bob Bays was interested in trying out the baseline audit process. Western’s VP of Canadian Operations, Bays says he wanted to be involved in learning how energy auditing will affect mining practices.

“We want to understand what the regulations’ impact on us are; plus, we want to be prepared and comfortable that we can meet those criteria,” he says. “This is consistent with our mission to run safe and efficient operations as well, so this is a way for us to do both things.”

Dr. Bamber strongly considers energy efficiency the next wave in a history of community-driven change that has pressed the mining industry to improve safety, environmental, and social practices over the past 30 years. It’s an area, he says, where there is significant room for improvement. Historic lows in energy prices during the 1990s, coupled with the freeing of international capital markets, has spawned a generation of mines driven by economies of scale with little regard for efficiency.

“Achieving true energy efficiency in mining is daunting,” Dr. Bamber says. “Mines have become inefficient because the key drivers for performance have not been energy-related — they’ve been cost efficient through simple economies of scale.”

With energy costs projected to go nowhere but up, with penalties and incentives associated with greenhouse gases imminent if not already in place, and social and regulatory pressures demanding steady improvement and reform, the baselining process developed will likely become a common tool for improving efficiency in mining operations in the future. Given its standardized methodology, baselining across the industry will open two paths towards efficiency. First, individual mines will be able to set targets for efficiency improvements and reliably measure results against their own baseline, tracking their gains over time. Second, being able to compare various processes at different mines with an “apples to apples” approach will allow benchmarking — the identification of best practices within the sector overall.

“There are going to be some new mines, and the ones we have are going to expand,” says BC Hydro’s Quon. “I want them to be able to take baseline data for all the coal mines and say okay, here’s one that runs really well in this process area, so here’s the best in class technology. Too often we see mining managers saying, ‘Well, let’s just copy Plant A because that’s the way we’ve always done it.”

Dr. Bamber suggests further efficiencies will be found by treating extraction, transport and processing operations as a continuous chain of activity, instead of independent functions. He tells a story of a mine that enjoyed substantial efficiencies because its processing and waste disposal facilities were located downhill from the mine itself, significantly reducing the amount of diesel transport required — a feature not previously evident using other baselining techniques. Understanding the impact of such features is critical in adopting more efficient designs in future.

Says Bamber, “Ordinarily when an engineer is sitting down to design a mine, her main design criteria are tonnage, or production capacity or safety, and so on. Energy is not a primary design criteria. What we’re suggesting in this “new world” of energy efficiency, having mines measured, taxed and possibly penalized based on energy intensity, is that energy efficiency should become a design criteria on the table from the beginning.”

Western Coal’s Bob Bays agrees this will be a challenge. But he says it’s worth it:

“Environmentally friendly companies are viewed much more favorably,”

he says. “[The baseline audit] is just good business and responsible business practice, so there’s no real downside to it. Even if there’s a cost associated with the initial application of technologies, it appears to us that long term it provides a financial benefit, so it’s just something you need to reconcile yourself with and budget as any normal business expense.”