Pub. 6 2016 Issue 2

13 MINING FOCUS The shop work schedule and the possibility of a fire in this area would also have to be considered. If the air quality is good enough to be reused in a mine, then it’s a good idea to evaluate the risks of doing so. Reusing shop air is a safety issue. It can only be done if risks can be alleviated in a way to ensure a safe environment. But if they can, then mine- level airflow could be increased substantially. • Auxiliary equipment areas. These all need ventilation, so the goal is to improve efficiency while the mine is being planned and then monitor it once it has been built in order to prevent inefficiencies. One way to do so is to redirect air within a travel way by redirecting a parallel split of the air. It can ventilate the auxiliary station instead of being sent directly to the return. • Dedicated intakes and returns. Mines expand and change over time, which means it might make sense to change the way intakes and returns are being used. For example, it might make sense to change some intakes to returns, and some returns to intakes. Computer modeling simulations can make it clear whether a change would be beneficial. • Optimization of mine development. Leaks are a fact of life in ventilation control structures. They always leak and they always deteriorate over time. To minimize leaks, the best idea is to reduce the number of ventilation structures. This can be done by increasing the distance between crosscuts, which minimizes the number of stoppings for each unit of development. It also saves installation costs and ventilation material, and it might cut down on the number of belt and power moves. However, it is important to be sure that the auxiliary ventilation system can handle any increased distance so that the face airflow will be adequate. • Use of mine airways. The goal should be to dilute contaminants in order to improve the working environment. Ventilation engineers can only succeed by understanding the way air flows through the mine and also being aware of air quality in the mine. • Alternativemethods of ventilating. If some areas of themine are hard to ventilate, installing a booster fan might make a difference. Controlled district recirculation is another possibility. However, it is important to keep in mind that a mine with many main fans will have complex air flow that isn’t always predictable. Sometimes fans can work against each other, for example. It is also a good idea to incorporate flexibility into mine ventilation. Sometimes a mine does not need to have the same flow of air at all times. Ventilation on demand (VOD) is a good way to make sure that the mine has air when and where air is necessary. Autonomous Mining Equipment The use of autonomous mining equipment is also an important trend, with companies like Rio Tinto setting the pace as they natural-gas generators that provide power for the mine’s auxiliary machines. Eric Svedlund, a product manager at Atlas Copco, explains the benefits of an electric underground truck this way: miners can almost double productivity and decrease the total cost of ownership by as much as 50 percent; ventilation needs go down because electric loaders don’t burn diesel; they use less energy, create less heat, and are approximately twice as fast as comparable diesel trucks. Improved Efficiency for Ventilation Systems A significant amount of time in mining is spent making sure there is enough air in the mines for the mines to continue running. Keeping mine air ventilated is expensive, so any improvements to existing systems benefit the mine financially and environmentally when done correctly. Of course, it is also important to understand any risks that might be involved and how changes might affect emergency and evacuation planning. Where do mining companies look when trying to improve mine airflow? • Underground shop air. Is it being sent directly to the returns? Operators do have some flexibility about how underground shop facilities are ventilated. The main issue is determining what contaminants are being produced in the work area. EQUIPMENT IMPROVEMENT continued on page 14