Dust is a serious health and safety concern for mining companies.
Strategies to manage the hazard have primarily centered on using water to capture and suppress the tiny airborne particles. Now, Temiskaming Industrial Mining Equipment Limited (TIME) has found a better solution for controlling dust.
What is different about TIME’s Proptec Rotary Mister is the way it generates and distributes consistently sized water droplets that travel far down drifts and ramps to capture dust particles.
“Xstrata put out a call to suppliers to help them determine if an atomizer used in agriculture could be developed for mining,” said Tate Byberg, TIME’s vice-president of sales. “Atomization products that simply spray water create a lot more hazards in the work space, causing more water problems, including slippery ramps and erosion.”
Fred Groulx, account manager at TIME’s Sudbury office, answered the call from Xstrata and contacted Richard Ledebuhr, vice-president of new product development at Ledebuhr Industries in Michigan. Ledebuhr Industries manufactures atomizers for agribusinesses. TIME, Xstrata and Ledbuhr worked collaboratively to design and manufacture the Proptec Rotary Mister for use in the mining industry.
Cheese grator
“The Proptec Rotary Mister works like a cheese grater with the basket spinning at 4,000 rpms to produce a fine mist. It creates millions of droplets that will stay airborne and capture the dust. The water is so fine, you can’t feel the wetness,” said Groulx.
“The ideal droplet size needs to be 50 to 60 microns. The conventional spray bar nozzle creates a droplet size of 400 microns.”
The mister is comprised of a propeller and hub. The propeller blades are made of high performance plastic and have several settings.
The aluminum hub provides the first stage of atomization by generating and dispersing large droplets into a stainless steel basket. The rotation speed fractures the large droplets into smaller sized droplets and propels them through a screen mesh made of Monel (70 per cent nickel and 30 per cent copper). A standard spray bar produces droplets more like rain and can only reach up to 12 metres in a drift, while the mister can reach 40 to 50 metres.
Compared to the standard spray bar with four nozzles that uses 17.5 gallons per minute in an eight-hour shift, the rotary mister uses only three gallons per minute, saving 14.5 gallons of water per minute. In addition, nozzles of the spray bars are prone to clogging, inconsistency, dripping and frequent maintenance. The mister, by comparison, requires minimal maintenance.
It can be powered by air, electricity or hydraulics, depending on use. It can also be fan assisted to create an air stream to transport the mist into a targeted zone.
Areas tested
The Proptec Rotary Mister was tested in several areas of the mine where dust was a problem. Travelways, where most of the dust is stirred up, was the first area tested. It was also attached to the back of a moving forklift to determine its effectiveness in reducing dust generated by moving vehicles. A crusher station where rock is falling onto a belt was another test site. On surface, it was tested in a location where trucks were dumping rock.
Byberg said he was skeptical at first, but once he saw how well it worked, he saw the potential.
Its primary function is reducing dust, but it also humidifies and cools the air. For mines with dry air, using the mister can provide regulated amounts of humidification. It can also be used as an evaporative cooler in high-temperature drifts.
The mister can operate 24 hours a day, seven days a week with no maintenance.
“Aside from controlling standard dust in work areas, it can also control gases and dust from blasting,” said Byberg.
TIME has its headquarters in New Liskeard with a 20,000-square foot manufacturing plant and branch offices in Sudbury, Val-d’Or, Red Lake and Timmins.
