The purpose of this evaluation was to characterize water quality and flow impacts on a sample of 16 permanent program underground mine permits with long-term pollutional discharges. In the study, quality and flow data was collected and annual treatment cost estimates developed on the sample permits. A comparison was made of the amount of bond on the site with an estimate of the annual treatment cost. The evaluation consisted of both field and file reviews on the sample permits.

Summary Findings:

• The average acid load from an underground mine discharge reviewed in the study was 32 times greater than the average for surface mines in a similar study done this year by the Field Office.
• The average iron load from a discharge from underground mines reviewed in the study was 178 times greater than the average for surface mines in a similar study.
• The average bond posted for the underground mines reviewed in this study was $1,168,614.00. The average estimated annual treatment cost calculated for the sample permits in this study was $252,286.00.

• OSM should perform further study of underground permits with large pollutional discharges to develop a complete database.
• Standardized annual treatment cost estimating techniques should be developed.

During this evaluation year, the Harrisburg Field Office (HFO) compiled an inventory (Acid Mine Drainage Inventory (AMDI)), of pollutional discharges in Pennsylvania. That inventory, which contains data on 500 permits, was created by digitizing printed reports of sites with discharges. The printed reports were provided at various times between 1995 and 1999 by PADEP. Not all of the data elements were available for all permits (See, Meta Data Report, EY 1999, Harrisburg Field Office).

This study and two similar studies were conducted by HFO to quality check OSM’s AMDI; to gather additional information characterizing the number and degree of off-site impacts; and to assess the amount of the bonds available to address the water quality impacts of the discharges.

The focus of this study is underground mines. It should be noted that, although Pennsylvania surface mines are covered by an alternative bonding system (bond pool), the underground mines are not, and are bonded at the full cost of reclamation. The minimum requirements for determining the amounts and time periods of liability for bonds for mining and reclamation operations in Pennsylvania are set forth in §§ 86.149 - 86.152.

Data Presentation and Discussion:

Of the 16 permanent program underground mine permits reviewed for this study, 11 had pollutional discharges requiring treatment. Each of the pollutional discharges were being treated to meet effluent standards at the time of the field review. These permits were mining in the Pittsburgh, the Upper Freeport, the Lower Freeport, the Upper Kittanning, the Lower Kittanning, the Middle Kittanning, the Lower Kittanning and the Clarion coal seams. The discharges were located in the Allegheny and Monongahela river basins.

Study data indicates that the average pollutional discharge from an underground mine produces significantly more pounds of pollutants per day than the average surface mine discharge. The average total load of pollutants (acid, iron and manganese) emitting from these underground mines was 43 times greater than that of the average surface mine (average of 7255 ppd underground versus 168 ppd surface).

The average bond held for the underground mines reviewed in this study was significantly greater than the average bond posted for surface mines (Table 1). The average bond amount of underground permits, with long-term pollutional discharges, reviewed in this study was $1,168,614.00. The average estimated annual treatment cost was $252,286.00.

In the sites reviewed, PADEP had not adjusted bonds to cover the cost of treating AMD when the underground mine permits were renewed or revised to add significant underground (shadow area) coal removal acreage. The average life of the pollutional discharges reviewed in this study was 25 years. All permits were reissued at primacy and are issued in renewable 5 year increments.

The receiving streams below nine of the treated pollutional discharges were judged to be of normal or higher water quality. Of those streams, eight would be moderately to significantly impacted should treatment be discontinued.

This evaluation consisted of detailed field and file reviews of underground mine permits with suspected long-term pollutional discharges. The forms, "Mine Site Evaluation" (MSE) and "OSM Mine Drainage Inventory" were completed for each site. In addition, OSM inspectors were asked to complete these forms during any inspection where a potential long-term pollutional discharge was noted.

Annual treatment costs for this study were calculated using a formula from Acid Mine Drainage Control and Treatment - Second Edition, Chapter 23, Compiled by Jeffrey G. Skousen and Paul F. Ziemkiewicz. The formula multiplies the flow of the discharge in gallons per minute, times the concentration of acid in the water in milligrams per liter, times .0022. This gives the number of tons of acid generated by the discharge per year. The tons of acid per year is then multiplied by a conversion factor ("Acid Mine Drainage Control and Treatment" (Skousen and Ziemkiewicz), Table 1, pg. 238) to determine the number of tons of treatment chemical required per year. The table also provides the 1996 costs of treatment chemicals at both bulk and normal rates. These costs can then be used to determine the annual treatment costs.

The cost calculations in this report use the average conversion factors (.57) and average bulk reagent costs ($496) for anhydrous ammonia and caustic soda. These treatment chemicals were chosen due to their relative low setup and maintenance costs.

The formula for calculating the estimated annual treatment for a discharge was:

flow * acidity * .0022 * .57 * $495.00

The cost estimate is for reagent to treat acid discharges only and does not consider treatment of alkaline or manganese discharges. Costs for maintenance, construction and sludge disposal for treatment facilities are also not considered.

The forms MSE and MDI were completed for each inspection. The MSE forms were input into the OSM I&E Tracking System by the inspectors. The "OSM Mine Drainage Inventory" forms (attached) were input into a Microsoft Access database designed for this purpose. Input of the MDI forms was by a program assistant.

This study did not evaluate the potential of the underground mines to continue to produce AMD after mining and pumping ceases.