• OPERATIONS
MANAGING COMPRESSED AIR
TO SAVE ENERGY
By MineARC
For modern mine sites , saving energy is critical . Whether cost or environmental considerations are the driving factor , reducing wasted energy use is a universal goal .
Electricity demands are increasing . South African mines ,
in particular , are experiencing the effects of increased load shedding and interrupted power supply . To face these demands , sites are seeking sustainable solutions to efficient energy usage such as those offered by compressed air management products .
Compressed air is vital to mining and underground construction . It is a popular method used in ventilation , material handling , tool operation , as well as other essential services due to its ease of use , reliability , and versatile nature . It is also used in a refuge chamber as the primary source of breathable air . However , its supply demands a high amount of resources and cost .
As it is such a prominent consumption of energy within multiple industries , the need arises for long-term sustainable initiatives to be developed . Compressed air accounts for a significant portion of electricity across the globe , and up to 20 % of the total mining energy consumption in South Africa .
A common misconception with compressed air systems is its seemingly lower costs . This myth has derived from an imperfect understanding or lack of tracking of compressed air . Typically , over 10 years , the energy cost of running a compressor system equates to almost three-quarters of its total expenditure . With this in mind , and the growing price and demands on electricity , improving efficiencies is vital for business .
Addressing compressed air usage There are several actions a company should take to address its compressed air usage . If it considers improving the efficiency of an existing system , a few simple steps will include :
• Review current and future air demand to ensure only appropriate equipment has compressed air connected
• Reduce compressed air wastage by identifying , measuring , and rectifying leakages
• Address pressure drops between the compressor and point of use
• Evaluate air receiver size to ensure storage meets the equipment demands
• Maintain and service the compressed air system regularly to prevent damage and exponential costs
• Ensure the system is adequate for work conducted on-site
Refuge chambers receive compressed air as the primary source of oxygen and to maintain positive internal pressure . Supported by a chemical scrubber which removes excess carbon monoxide and carbon dioxide , the air supply is the most accessible option .
Air is connected to the chamber via the main air lines and filtered to manufacturing specifications and mine safety guidelines ; MineARC adheres to the AS / NZS 1716 specifications .
Internal positive pressure prevents hazardous substances , such as smoke , from entering the chamber . To reach this , the flow rate of compressed air should be set to maintain a small overpressure , relative to the external pressure . Check valves attached to a chamber vent excess pressure if the maximum airflow if reached ; its selfsealing nature maintains the sealed environment .
Refuge chambers receive compressed air as the primary source of oxygen and to maintain positive internal pressure .
22 • African
Mining • February 2021
All images : MineARC
A study in mine compressed air simulations Simulations are used to test and identify cost and operational improvements across multiple worksites . There have been several studies utilising alternate simulation techniques to identify efficiencies in compressed air systems .
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