Web Exclusive: Tailings management

By |  August 16, 2011

Rheomax from BASF is an innovative tailings-management technology that allows the aggregates and mining industries to rapidly restore mine sites to their natural state. The Canadian patent office recently granted the company a patent for this technology.

Rheomax offers a solution to an industry that continues to be challenged by issues relating to the use of water and the impact of exploration, extraction and disposal activities on the environment. These include minimizing water consumption, maximizing recovery of process water, reducing land area consumed by tailings and minimizing the costs and time required to rehabilitate such land. Rheomax is suitable for use in mineral and metal processing, including oil sands processing.

“We are very pleased that we have been granted this patent so that we can put this technology to use here in Canada as it has been used in several other locations including in Australia, Europe and South America,” says Chalmers Reed, sales manager, Mining Chemicals North America. “This allows the Canadian mining industry to meet the environmental challenge of reclaiming the land while still meeting global consumer demands for energy.”

The Rheomax technology is well suited to the aggregates industry. The technology makes the tailings and wash water more homogeneous, captures the fines and reduces the stratification normally associated with these substrates. This results in faster release of cleaner water and leaves the solids drier and trafficable in a short time. The product range is broad enough to guarantee an appropriate charge and molecular weight material to provide optimal results. Additionally, BASF provides the equipment and application expertise to select the best products, and application points to ensure the desired effect.

How it works

Existing ponds must be dredged from the pond to an adjacent site. During the dredging and pumping phase, Rheomax is added to the piping to achieve the effect that will be seen when the substrate is discharged. Although it may appear similar to some flocculent addition strategies previously employed, the polymers used and the application technology are unique and patented, and result in a much different matrix that dewaters quickly, is not at all dependant on atmospheric drying, and requires no manipulation or compression to extract the normally trapped water.

Tailings are a mixture of water, fine clay, sand and residual bitumen that is deposited into tailings ponds. These tailings ponds are often large and negatively impact the landscape and environment. Returning a tailings pond to a landscape of vegetation and trees can take several decades, because the fine silts in the ponds settle to the bottom very slowly or can remain in suspension indefinitely.

With Rheomax, the dewatering, recovery and recycling of tailings ponds has been greatly accelerated so that fewer and smaller tailings ponds are needed. The process binds all the solid particles, fine and coarse, together in a homogeneous particulate structure that quickly and effectively releases the trapped water from the tailings. This recovered water is clean enough to be recycled back into the process while the solids are left to dry, compact and can begin supporting growth of vegetation in a matter of weeks.

So what once took decades, can now take just weeks or months, allowing the tailings ponds to be drained and the land to be reclaimed so that it can be quickly returned to its natural state.

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About the Author:

Darren Constantino is an editor of Pit & Quarry magazine. He can be reached at dconstantino@northcoastmedia.net.

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