Landfarm Rehabilitation: Coal Mountain, Elk Valley Coal
Elk Valley’s Coal Mountain Operation faced the challenge of shifting tonnes of hazardous waste to make space could for other purposes. Following the presentation of a new product by a waste management contractor, Environmental Officer Warn Franklin took the initiative to develop an environmentally-friendly remediation technique that saved the Operation a great deal of time and money. Here, Warn answers some questions and tells the story in his own words:
What is a landfarm, exactly?
Contrary to other dump sites at a mine, a landfarm is set up for dealing with hydrocarbon-contaminated soil created through on-site oil spills or hydraulic oil spills, and also contains hydrocarbon-contaminated sediment from the steam wash bay. Waste sent to a landfarm really has nothing to do with mining process, but comes from the equipment involved.
Why was Coal Mountain in a rush to move this landfarm?
Because it was in the way – we had planned on dumping right overtop, and so needed to remediate it as soon as possible. We could either ship the waste offsite, which would’ve meant paying someone else to solve our problem, or we could try something new. A waste management contractor told us about new corn- and bran-based hydrocarbon-degrading granular bacteria, which is quite a bit more concentrated than the standard absorbent usually used in remediation. It piqued our interest, and we started researching what it could do for us.
What’s so special about these bacteria?
The granular blend is made up of naturally-occurring, scientifically-selected microbes. There are no genetically-modified organisms, and the blend is biodegradable, non-toxic, non-caustic, non-acidic and non-pathogenic. The bacteria in the blend are specifically chosen for their ability to consume hydrocarbons; they feed on the contamination, deriving nutrition for growth and reproduction. The hydrocarbons are metabolized by the bacteria and reduced to water and carbon dioxide; the contamination is consumed completely or reduced to safe compounds.
After deciding to test it on eight landfarm cells, we had to move quickly; we had only the short window of time between August and September, because bacteria perform better in summer temperatures. We added straw, hay, fertilizer and a non-toxic, non-corrosive and environmentally-friendly reliquification product – it smells like grapefruit! Each ingredient plays an integral role in the mix:
- the reliquification product separates hydrocarbon (oil) from the soil particles so that bacteria can get at it more readily
- the straw and hay act as bulking agents, which provide oxygen for the soil and a carbon source for the bacteria
- fertilizer supplies the bacteria with nutrients
Did it work?
The initial application was on August 9 and cells were given a ‘booster shot’, as per manufacturer’s recommendations, on August 23. Landfarms were tilled with an excavator every week; a good stirring ensured that additives were dispersed thoroughly to produce optimum results and to aerate the soil. We took care to provide the mix with lots of water – we needed to maintain 30% moisture to keep the bacteria happy.
The results were astounding: out of the eight cells total, only one failed the Contaminated Sites Regulation cut-offs, because hydrocarbon levels were unfortunately just a sliver too high to meet the requirements.
How is Coal Mountain’s remediation process different from ‘business as usual’?
By handling the problem ourselves, we saved the money that would’ve been spent either building a new landfarm or hiring a waste management contractor to haul the material off-site. This also allowed us to ensure that the waste was treated in an environmentally-sound manner.
Those considerations aside, our unique mix was the main difference. Traditional methods use a fibre-based product that’s inoculated with microbes –this serves as an absorbent first, and its microbial properties play a secondary role. Standard methods may take longer than one year to yield success, while ours had a two-month turnaround.
Our soil, which had formerly been hazardous waste, has since been used as cover soil on our coarse coal refuse slopes. It will be grass-seeded, and will contribute towards our Operation’s reclamation efforts.
Yes, this was an experiment, but we were committed to doing it right –not using products or a methodology that would potentially leave more of a mess behind.