By Ivan Cooper

Tightening environmental regulations are intended to protect natural resources such as water, and mining companies need to have a clear idea of how regulations will change so that they can continue to operate cost-effectively.

Many coal companies are finding that with each environmental permit expiry, the allowable water effluent limits have become more stringent for the permit’s renewal. This means that companies are paying increasing attention to meeting the tightening requirements for treating water. If they can find reliable solutions for meeting rising regulatory requirements, mining companies are then able to focus on operational issues such as extraction plans and processing efficiencies. So, what’s changing in regard to the need to treat water effluent from coal mining?

New Environmental and Regulatory Concerns on Mine Water

Changing environmental regulations are driven largely by developing a scientific understanding of how the environment works, and how human activity is affecting it. Some of the trends regarding water effluent from coal mining and handling have emerged.

There has been a long-standing concern about the effects of total dissolved solids, chlorides, iron, aluminum, manganese, mercury, and radioactivity that can be released by coal extraction and combustion.

The industry now sees growing concern about selenium, which is driving tighter regulations on its control. The increased awareness of selenium as a chemical that is being more closely regulated, along with dispersed sources at mine sites and difficult and expensive treatment options are increasing concerns. The Environmental Protection Agency’s (EPA) proposed Effluent Limitation Guidelines (ELGs) for selenium at the low parts per billion level for the Electric Utility Industry highlight these issues.

Some regulatory agencies and lawmakers are pushing for tighter regulations on releases of nutrients into surface water, which can cause algae blooms that reduce oxygen levels and have impacts on other aquatic species. This has implications for blasting operations necessary to remove development rock, which can release nitrates into the water.

Growth in site-specific regulations stems from improved scientific understanding of geology and hydrology, allowing for finer tuning of regulations to meet the purposes of environmental protection for each context. This means that companies need to have a better understanding of site characteristics for each of their locations to develop plans to meet regulations that apply at those locations.

Perhaps the biggest trend in water-related regulations is a general tightening of requirements. Accordingly, mining companies must be prepared to future-proof their physical plant so that the equipment and procedures now in place can meet tighter regulations in the future. As a result, the physical plant, methodologies and staffing will remain effective for a longer period of time, allowing for better return on investment.

There is also a growth in public concern about the effects of coal extraction in general, and that extends to water impacts. Environmental organizations have had the industry in their cross-hairs for some time and they make available a wide range of information about the industry and its environmental effects. Despite efforts from the industry to tell the other side of the story, social media is helping fuel public concern about the industry — which is one of the drivers for the tightened environmental regulations.

The overall result is that water effluent concerns have moved higher up on the agenda of the coal industry. Without regulatory approval, all the work on efficient operations goes to no account, because production is slowed or stopped. While all mine operations have a bottleneck, the water treatment system should not be a limiting factor.

Why the Reactive Approach to Water Treatment Often Fails
Experience helping mining companies meet water standards has revealed that some industry members could do better in terms of planning their investments in technology. What often happens is that the mine’s management finds that the effluent levels for the renewed permit cannot be met with the equipment now in place.

In many cases, their first approach is to contact an equipment vendor they’ve worked with before to see if there is a solution that will meet the tightened requirements. The vendor may do some analysis of the effluent and make a recommendation for a solution. The “solution” shows up at the mine site on a series of flatbed trucks, is installed and staff are trained in its use.

If the analysis of the effluent was done hastily, the equipment installed may not meet regulatory requirements. Faced with a looming deadline, the mine management team looks for another equipment purchase to help the operation meet requirements, which may or may not be effective for the task at hand.

Or it could be that while the equipment does the job of cleaning the effluent, it does so inefficiently — the nature of the effluent is such that treating it involves far more of some chemical inputs than was expected. For example, with an ion-exchange system, there may be other ions in the effluent that are taking up the media exchange capacity too quickly. Sometimes, the equipment may be ineffective at picking up the sulfates in the effluent.

The result may be higher costs for process additives than was expected, or higher maintenance costs and staff time requirements, or more breakdowns and need for repair. Sometimes there are operational changes that overwhelm a water treatment solution that had been working effectively. This could be because output has increased to meet demand, or a new area of the resource has come on stream, resulting in more water effluent. This underlines the need to choose solutions that future-proof the mine operation, including the water treatment system.

Mine Effluent Treatment Needs a Structured Approach
Ideally, coal operators should take a structured approach to selecting mine effluent treatment technologies. While equipment vendors are part of this process, their role generally comes more toward the end, when they are asked to provide information on the capabilities of specific pieces of equipment, and later to provide training and trouble shooting.

The structured approach starts by working with a qualified professional team whose members are able to carry out a thorough analysis of the situation and recommend which solutions will be best. This team might be from inside the company or external. Often, the best results come from using some personnel from inside the company who are familiar with the way the work is done and the political realities, and external members who may have a broader understanding of how various technology solutions have worked on other sites.

A systematic approach involves a multistage process:

  • Source definition — water flow rates, material mass, solute concentrations, expected duration, etc.
  • Reliability in meeting effluent goals
  • Identification of environmental goals — discharge standards, compliance points, and human or ecological risks.
  • Identification of applicable technologies — finding out which technologies are potentially capable of meeting goals.
  • Identification of critical parameters — early determination of values for parameters that typically drive cost or effectiveness.
  • Impartial evaluation — a feasibility analysis that is completely independent from technology vendors.
  • Fatal flaw analysis — finding out if there are any critical factors that prevent implementation.
  • Operation ease
  • Capital and O&M costs
  • Rating — relative importance and rating and weighting of factors.
  • Head-on-head comparison — pair-wise with numerical score.


Full Awareness of Available Alternatives
One of the advantages of retaining external professional expertise is that the people involved are likely to have a good understanding of the wide array of water technology solutions available. These can range from passive systems, such as aerobic and anaerobic wetlands, to higher-maintenance systems, such as reverse osmosis and precipitation processes.

All of these systems have their relative merits. For example, wetland systems may not perform to the standard required during winter months. Other systems may not be optimal in areas where skilled maintenance personnel are required.

A structured approach may take longer up front, partly because of the amount of information to be gathered. But it is time well spent — the solution that is chosen is more likely to be effective at solving the problem, with adequate consideration given to the changing operation of the mine and to future regulatory changes.

About the Author
Ivan A. Cooper, PE, BCEE, is principal and national water/wastewater practice lead for Civil & Environmental Consultants Inc. in Charlotte, North Carolina. Contact:; 980.237.0373. This article is based on the paper, A structured approach for selecting mine effluent treatment technologies, that the author presented at the SME Annual Meeting in Salt Lake City, Utah, in February, available at