What to do with millions of gallons of water in a coal mine

Overview
This learning episode was developed as a result of an actual occurrence in a midwestern state in 1993. The core of this episode is a simulated watershed meeting at which the mine dilemma will be addressed. In preparation for and as an extension of the meeting, learners will explore many of the scientific, economic and social aspects of an environmental dilemma.

Grade level range:
Middle School, High School

Illustrative Instructional Objective Learners will seek elaboration and justification of data and ideas, investigate models and theories that help explain the mine and watershed system, participate actively in dialogue about and resolution of this environmental issue, and study and propose improvement in public decision-making activities of the stakeholders.

Background
Water held in an abandoned portion of an active underground coal mine worked its way under an engineered barrier and flowed into much of the remainder of the mine. The company which owned the mine was faced with a difficult situation. Unless this water was quickly pumped from the mine, the rock strata in the mine roof, floor, and walls, as well as the mining equipment, would be permanently damaged. The damage would force the mine to close, and the workers would be unemployed. In addition, economic effects from the mine closing could force the closing of a sister mine. The mine is in an economically depressed area of the state where there are few good-paying jobs. The coal from these mines, which was used to produce electricity at a nearby power plant, would have to be replaced with coal from other sources, the costs and reliability of which were uncertain.

The streams into which the mine water would be pumped (released) did not provide public drinking water supplies and were already affected by existing drainage from old abandoned surface mines in the area. Scientific surveys showed 90 percent of the fish in the streams were minnow species.

Unfortunately, the mine water had a high iron content and acidity level. Under normal operation conditions, water from the mine passes through a water treatment facility, where chemicals are added to raise its pH (lower its acidity). The process of raising the pH of the water causes the formation of a brown iron hydroxide precipitate. This precipitate is allowed to settle out in specially constructed settling ponds. The treated water, which meets all environmental standards, is then released from the pond into receiving streams. The water treatment process protects aquatic life in the receiving streams and also ensures that the streams can be used for other purposes, such as livestock watering and fishing.

The dilemma was posed because the settling ponds at the existing mine water treatment facility did not have the capacity to fully treat the quantities of water which would have to be pumped in order to de-water the mine before serious damage to the roof, floor, and equipment had occurred.

If the water were pumped into the stream totally untreated, most aquatic life in the stream would be killed. On the other hand, treating the water for acidity but not allowing the iron hydroxide to settle would result in the brown precipitate covering the bottom of the stream. This would affect fewer fish immediately, but would ruin the habitat of bottom-dwelling organisms, including insects and fresh-water mussels, and would thus slow the eventual recovery of all aquatic life in the food web. It was agreed by all concerned that treatment of the water in place, i.e., in the mine, was not feasible.

The company hired ecological experts to work with its own environmental and engineering specialists to come up with a plan to remove the water quickly with the least environmental effect. Discussions between these company representatives and state environmental agencies resulted in a plan to pump the water from the mine, raise its pH slightly (but not enough to create a significant accumulation of precipitate on the creek bottom), and release it into the creek. Several small ponds were quickly constructed to give the chemical used to raise the pH sufficient time to thoroughly mix with the mine water.

This plan was based on a combination of field observations and studies of scientific literature, all of which were undertaken before pumping began. In the field, scientific assessments were made of the types of aquatic life living in the main stream and nearby unaffected streams, of the habitat afforded by the steams, and of the availability of nearby sources of aquatic life to recolonize the stream to be affected. Specialists reviewed the scientific data available on the effects of lower pH, high-iron water on aquatic life, and on the nature and time scale of stream recovery from an environmental disturbance of this type. The state environmental agency also reviewed its own data on the recovery of another stream which it had studied extensively. The prediction of both company and agency scientists was that although immediate damage to the stream would be severe, there would be no permanent effects on the stream or aquatic habitat. Natural recovery of the aquatic life was expected to occur within two years.

The results of the pumping were as expected. Most of the aquatic life which remained in the primary receiving stream did not survive the mine water release. However, the habitat for aquatic life was not significantly altered, which allowed for natural repopulation of the stream. Water quality returned to normal shortly after pumping ceased. Natural stream recovery was permitted to take place, with the company taking some steps as advised by natural resource experts to accelerate the natural process. Although the environment was temporarily degraded, it was restored and no jobs were permanently lost. The mine reopened after seven months of work to rehabilitate the mine's structure and underground equipment. All employees idled by the water problem returned to their jobs.

Procedure
1. Distribute learner information sheets (attachment) and brainstorm scientific, economic and social issues involved in this case study. List the different interests involved.

2. Leaders and learners together should devise a plan for gathering information, presenting the different sides of the issue, and evaluating the project. Differing perspectives representing scientific, economic and social interests should be addressed. Related activities might include:

• Investigating the life cycle of common organisms found in nearby streams.
• Describing the food web associated with aquatic life in a freshwater creek.
• Monitoring the water quality of a nearby creek by observing aquatic macro-invertebrates.
• Watching and discussing videos of fish sampling and laboratory testing.
• Exploring the long- and short-term impact on the aquatic ecosystem of the stream.
• Analyzing the potential economic issues related to the flooding of the coal mine and the subsequent release of the mine water into a creek.
• Investigating the role the mine played in the local community.
• Exploring the local support for the mine, i.e., interviewing people involved in mining both on the management and the labor sides or conducting a community survey.
• Investigating the properties of acids and bases.
• Studying pH levels and how they change.
• Researching how aquatic organisms react differently to water containing iron, depending upon the metal's form and concentration.
• Investigating the chemical reactions that would occur as various chemicals were added to water and improve the pH level (use the sample activity below).
• Noting similarities and differences between experiments they might conduct and actual treatment of water from the coal mine.
• Exploring the long- and short-term aesthetic impact on the area.
• Research the origins, mining and uses of coal.
• Improving communication and cooperation skills as the pros and cons of possible solutions to this environmental problem are debated.
• Researching the correct procedures for conducting a town (watershed) meeting and setting the rules for the simulation.
• Conducting the following demonstration to simulate one way to treat mine water:
  
  Measure one teaspoon of ferrous sulphate powder into a paper cup. Add a tablespoon of white vinegar. Observe this solution, which represents the acid mine water with iron in a non-precipitate form. (The solution should be clear). Test with litmus paper (which should show a low pH). Add one to two tablespoons of baking soda to the solution which now represents mine water to which a base has been added. Very gently blow bubbles into the solution or stir to aerate the solution and mix the baking soda thoroughly. Observe the solution again. (A dark brown stain and a coating of precipitate should be visible). This simulates the normal treatment mine water would receive, with the precipitate then settling out in specially constructed ponds. In the environmental dilemma, time did not permit this full treatment of the mine water.

3. Conduct the watershed meeting with learners taking the roles of the following:

• an officer to preside over the meeting
• mine representatives including owner, manager, environmental and engineering experts, workers
• watershed landowners including farmers
• personnel from government agencies responsible for environmental regulation, wildlife, mining
• representatives from environmental groups
• media representatives
• scientist(s) from local college
• governor's office
• state legislators

4. Learners not assigned to specific roles would still participate in the discussion and decision-making part of the meeting as general watershed residents.

The meeting should result in a formal list of recommendations on how to best resolve this dilemma. Share the actual strategies that were used in the "real life" mine flood occurrence as well as the results, and compare with the student recommendations. Allow learners to discuss the differences and similarities, and the pros and cons of each.

Assessment
Learners should take an active role in defining and choosing assessment strategies. Assessment tools could include one or more of the following:

• Preparing an audio-visual program which illustrates and explains one of our serious environmental problems and technologies and practices which can be applied to solve it.
• Distinguishing between facts, opinions, and opinions stated as facts by reviewing newspaper articles on environmental issues -- can you tell which side of an issue was supported by the magazine or newspaper that reported it?
• Developing an attitude survey which solicits responses from students and parents about an environmental issue -- then compiling the results and preparing a chart or exhibit comparing the results.
• Researching local laws, ordinances, and information related to a particular environmental issue including the environmental safeguards and costs of compliance.
• Attending a community meeting and reporting on it to the class.
• Designing a display showing the differing viewpoints on a specific environmental issue.

Materials
Will vary according to activities chosen.

Learner information sheet
What to do with a million gallons of water in a coal mine

Problem
Water stored in an abandoned portion of an active underground coal mine has broken through an engineered barrier and flowed into the remainder of the mine. If left in the mine, this water will quickly damage the rock strata in the mine roof, floor, and walls, as well as the mining equipment. The damage will force the mine to permanently close. The coal miners will be unemployed, and the coal used to produce electricity at a nearby power plant will have to obtained from other sources.

Unfortunately, the mine water has a high iron content and is very acidic. Under normal operation conditions, water from the mine passes through a water treatment facility, where chemicals are added to raise its pH (lower the acidity). The process of raising the pH of the water causes the formation of a brown iron hydroxide precipitate. This precipitate is allowed to settle out in specifically constructed settling ponds. The treated water, which meets all environmental standards, is then released from the ponds into receiving streams. The water treatment process protects aquatic life in the receiving streams and also ensures that the streams can be used for other purposes, such as livestock watering and fishing.

This is a dilemma because the settling ponds at the existing mine water treatment facility do not have the capacity to fully treat the quantities of water which would have to be pumped in order to de-water the mine before serious damage to the roof, floor, and equipment had occurred. If the water is released totally untreated, most aquatic life in the stream will not survive. On the other hand, treating the water for acidity but not allowing the iron hydroxide to settle will result in the brown precipitate covering the bottom of the stream. This will affect fewer fish immediately, but will ruin the habitat of bottom-dwelling organism, including insects and fresh-water mussels, and will thus slow the eventual recovery of all aquatic life in the food web. Treatment of the water in the mine is not feasible.

Possible solutions (there may be others - be creative!)

1. Leave the water in the mine. This would necessitate closing the mine and the permanent loss of the mining jobs and equipment.

2. Pump the water from the mine and release it, untreated, into the stream.

3. Pump the water from the mine, raise its pH slightly (but not enough to create a significant accumulation of precipitate on the creek bottom), and release it to the creek.

Several small ponds could be quickly constructed to give the chemical used to raise the pH sufficient time to thoroughly mix with the mine water. This would most likely cause immediate loss of aquatic life in the stream. Natural recovery from this temporary impact would be accelerated by company activities and would be expected to occur within two years.

4. Pump the water from the mine and fully treat it to prevent any effects to the receiving stream. As mentioned above, this could not be completed in time to prevent serious damage to the roof, floor and equipment in the mine.