By Dave Grottenthaler and Paul Rey
It’s no secret the coal mining industry is facing many challenges today. From legal wrangling over mountaintop mining to lower demand, coal companies’ revenues are taking significant hits.
Environmental compliance continues to be a growing challenge for the industry as well, including treatment of acid mine drainage (AMD) and alkaline mine drainage. The treatment is an ongoing requirement for coal companies, even if they are in a post-coal mining situation. Mine drainage is an expense and it continually strips away profit from the companies’ bottom line. Mines that no longer yield coal continually collect water and that water will still need to be treated prior to discharge. New permits can be blocked if the owners of the hundreds of inactive and closed mine sites that exist today don’t comply with federal and state governments environmental regulations.
However, the remediation of AMD does not have to be economically burdensome. There are new cost-effective treatment technologies, including new chemistries, treatment schemes, mechanical improvements, analytical techniques and automation. Surprisingly, though, many mine owners remain mired in the past.
The traditional method for removing iron and other metals from mine drainage has consisted of a combination of increasing pH in conjunction with sedimentation. These processes include feeding lime, ammonia, caustic and other alkalies. Today, that standard approach is becoming obsolete as more effective treatment methods are developed.
Often times mine water that is actually alkaline in nature is treated with lime or caustic, and this treatment actually makes the water more scale forming and increases the staining in the receiving streambed. Instead of feeding lime or caustic, adding an oxidizing agent and a scale control product to the mine drainage water allows for metals removal and a stream bed that is free of unsightly deposits.
The process allows the treated water to be safely returned to the environment and does not affect the appearance of the receiving stream’s bed. In fact, the effectiveness of these processes has been validated through two U.S. patents awarded to Kroff Chemical Co.
In West Virginia, where 53 of its 55 counties have coal and 43 of those have reserves of minable coal, government regulations are the most stringent of all coal-producing states. Metals such as aluminum and selenium are being added across the board to discharge permits. Also, mining companies are having the added responsibility for controlling staining, discoloration at the outfall, and foaming issues that can result from the discharge of treated mine drainage.
With newly developed treatment approaches involving the feed of specialty chemicals at low, economic levels to the effluent discharge pond, mine owners can prevent calcium carbonate from forming on streambed rocks. Staining in the discharge stream is eliminated, and the chemicals that were previously used to control the staining will likely no longer be necessary. Mine owners will save significant money because they’ll use fewer chemicals, generate less sludge and avoid outfall violations and associated costs.
Many coal operators don’t know they’re hurting because they aren’t aware of more economical alternatives to their current method of treatment. Consider the mine owner who was using a $1 million a year treatment process that involved caustic soda, alum, hydrochloric acid and anionic polymer to remove iron and control pH. By eliminating those commodity chemicals and replacing them with Kroff’s proprietary specialty chemicals, the annual treatment remediation budget dropped to $300,000.
Another example of improved technology for AMD applications is the freeze-protected products developed by Kroff Chemical. National Pollutant Discharge Elimination System regulations govern many locations, including mines that are inactive or closed. In areas where there is either no electricity or generator-powered electric, these chemicals can be fed year round even in winter conditions.
From metals abatement, to weather protection of chemicals, to on-site use of sophisticated spectrophotometers that are highly accurate, treatment of mine drainage has evolved. Working with more than 50 sites in West Virginia, Pennsylvania, and Kentucky, Kroff Chemical has in many ways led the evolution.
Closed mines made their money in their day, but they now detract from mining companies’ bottom line. Every time a coal company’s chief financial officer, environmental manager or director of safety, health and environment cringes at the thought of literally dumping money into a worthless hole, he or she should first consider whether state-of-the-art or antiquated processes dictate the company’s AMD management.
If it’s the former, the first step should be finding a chemical company that can be a partner in offering customized, cost-effective solutions to compliance challenges, rather than relying on one-size-fits-all commodity approaches. Looking beyond the old standards can bring clarity to a cloudy treatment issue and produce a fresh picture for the bottom line.
Grottenthaler is general manager of operations for Kroff Chemical. He can be reached at 412-999-2049 or firstname.lastname@example.org. Rey, co-author of
this article is the inventor of the patents mentioned. He can be reached at email@example.com.