For years now, the float and sink method for testing coal has been accepted as standard practice. However, the method is not without harmful complications. Researches are examining a new water-based coal testing method which may overcome these.
In exciting news, the new technique for testing metallurgical coal samples may not only be more precise and quicker, it also has the potential to be better for the environment. The traditional float and sink method, which is widely practiced, uses a range of carcinogenic chemicals to test the properties of coal and determine the economic viability of potential new coal mining sites. These chemicals wash and test, with consideration to the relative density, a range of coal types, in order to remove ash and other impurities.
“The medium used to separate particles into their various density fractions is generally a mixture of organic liquids, specifically Tetrabromoethane (TBE), Bromoform, Perchloroethelyene, and White Spirit. These organic liquids are toxic, environmentally hazardous and may also interfere with the properties of interest for a coal producer or end user.” Michael Campbell and Robert England of ALS Coal Technology
The existing testing methods, and the chemicals involved are dangerous to the environment, and pose health risks to the laboratory workers responsible for them. White spirit, methylene bromide, and perchloroethylene or PCE are used in the testing; PCE in particular is recognised as a carcinogen and was used for years in the dry-cleaning industry before the health risks were deemed too great. Several alternative methods have been tested in recent decades, which aimed to reduce the potential harmful effects of the float and sink method, and yet it still remains the most commonly used approach. The research project to test this latest method is being conducted by CCRA (the Canadian Carbonisation Research Association) and Geoscience BC, and hopes to verify the effectiveness of a water-based process called the Roben Jig method.
Using a ‘jigging’ action, a specially designed motor and cylinder sort coal particles using water, to separate samples of different densities.
“The potential of finding a faster, safer more reliable method of determining coal quality is a real boon for the coal industry,” said Geoscience BC’s vice president of minerals and mining, Bruce Madu. “Ultimately, the more accurate information a prospector or company has about the quality of coal beneath the ground, the higher the value they could get for their property or the end product.”
Needless to say, the results of this study may present huge benefits to the international coal industry and represent an important move away from the use of harmful chemicals on both the environment and the workers involved in the testing. The results will be available later this year, from Geoscience BC.