Al:stract. The effectiveness of preventing or ameliorating acid mine drainage (AMD) through the application of alkaline additives is evaluated for eight surface coal mines in Pennsylvania. Many of the mine sites had overb.Jrden characteristics that made prediction of post-mining water quality uncertain. Alkaline materials were applied at rates ranging from 42 to greater than 1,000 tons as calcium carlx>nate per acre. In addition, two sites that were mined and reclaimed without alkaline ad.di ti ves are included for cx,mparati ve puq:oses. OVerb.rrden sulfur concentration and 11 neutra1ization PJtential 11 (NP) data for I!D.lltiple strata at each mine site were used to cx:m,pute the Cl.Ill1Ulati ve, mass-weighted 11 maxinn.nn J;X)tential acidity" (MPA) and 11 net neutralization p:>tential 11 (NNP = NP-MPA) by using three different calculation methods. Post-reclamation water-quality data were used to cx:m,pute the net alkalinity (= alkalinity-acidity). The Il'OSt conservative detennination of NNP, whereby MPA is calculated by multiplying the total sulfur concentration, in weight percent, by 62.5 instead of 31.25, yielded the best agreement with net alkalinity (matching signs on NNP and net alkalinity). The error in prediction using each method was that the reclaimed overburden was computed to be alkaline overall (NNP > O), tut the post-reclamation water was acid (net alkalinity < o) • In general, alkaline addition rates were probably insufficient to neutralize, or too late to prevent, acid prcx:iuction in the mine SIXJil. At six of the seven mine sites that had overb.Jrden with insufficient NP relative to MPA (NNP < O), the addition of alkaline materials failed to create alkaline mine drainage; AMO was fonned or persisted. A control site which also had insufficient alkaline material, b.lt did not incorp:,rate alkaline additives, generated severe AMO. Two sites that had substantial, natural alkaline overburden produce:l alkaline drainage. Although the addition rates appear to be inadequate, other factors, such as unequal distribution and exposure of the acid-fonning or neutralizing materials and hydrogeological variability, complicate the evaluation of relative effectiveness of using different alkaline materials and placement of the acid-or alkalineprcx:iucing materials.

Abstract:The effectiveness of Acid-Base Accounting (ABA) for predicting surface coal mine drainage quality in Pennsylvania was evaluated. Comparisons between ABA and mine drainage alkalinity, acidity, and sulfate were made for 38 mines in the bituminous coalfield. Neutralization Potential (NP), Maximum Potential Acidity (MPA), and Net Neutralization Potential (NNP) were evaluated with and without "thresholds."Calculations using "thresholds" counted only those values for NP greater than 30 mt CaC03/l,OOO mt and percent sulfur greater than o. 5%. "Without thresholds" computations included all values. Stoichiometric equivalence factors of 31.25 and 62.5 were used to compute MPA. NP and NNP are the best predictors of postmining drainage quality. Alkaline or acid drainage quality is controlled by as little as 1% to 3% carbonate in the overburden. NNP less than 1% generally results in acidic drainage, and NNP greater than 3% yields alkaline drainage. An empirical relation exists between alkalinity and NP. Postmining alkalinity can be estimated as 4 to 6 times NP (without thresholds) .MPA is not a reliable predictor of drainage quality, except in the absence of calcareous strata, where a positive relation exists between acidity and MPA.

he addition of alkaline materials to supplement deficient "neutralization p:,tential 11 (NP) of mine s:i;x:>il, and thus to prevent or abate acid mine drainage, has not been successful at rrost surface coal mines in Pennsylvania. A basic problem may have been improper accounting for acid-prcx:luction {X)tential and thus. inad~te addition rates of calcium carb:mate (Caoo 3 ), calcnnn o,ade (Cao), or calcilnn hydroxide [Ca(OH)il at many mines. The comnonly used acid-base accounting method is based on the following overall reaction:FeSz + 2 CaCXl:J + 3. 75 Oz + 1.5 HzO

On 01/25/05, a 10,000-gpm "blowout" of the century-old Nickle Plate Mine (Pittsburgh coalbed) occurred in a public sidewalk about 12 miles southwest of downtown Pittsburgh, PA. The US Office of Surface Mining, first responder, installed diesel pumps and drain lines along public streets to control and convey the discharge to a nearby stream. On 02/22/05, the Pennsylvania Department of Environmental Protection, Bureau of Abandoned Mine Reclamation issued a 90-day emergency contract to Environmentally Innovative Solutions, LLC to provide a permanent control. With numerous partners (federal, state, local agencies; local residents and businesses), property access, stream and mine pool water quality data, historical mine mapping, and other pertinent site information were acquired. Nine options were developed and evaluated. Paramount in design considerations was public health and safety followed by effectiveness, reliability, community and environmental impact, long-term maintenance requirements, installation cost, and aiding future work including grouting to address mine subsidence issues and treatment of the abandoned mine drainage. Piezometers and test pits were installed in city streets, private driveways, and on undeveloped property and mine pool response tests were conducted. After data evaluation, the mine pool was manipulated to discharge about ½-mile northeast of the "blowout" on undeveloped land to an AMD-degraded receiving stream. By 05/20/05, a primary gravity drain, a secondary drain, and an early warning system at the "blowout" had been completed. Subsequent monitoring confirms the facilities are functioning as designed.

Abstract. Pennsylvania enacted an Environmental Good Samaritan Act (PA EGSA) in 1999. The law is intended to encourage landowners and others to reclaim abandoned mineral extraction lands and abate water pollution caused by abandoned mines or orphaned oil and gas wells. The law protects landowners, groups and individuals who volunteer to do such projects from civil and environmental liability under Pennsylvania law. Prior to the PA EGSA, anyone who voluntarily reclaimed abandoned lands or treated water pollution for which they were not liable could be held responsible for treating the residual pollution under Pennsylvania law. This dissuaded people and groups from pursuing these types of projects. Only projects approved by the Pennsylvania Department of Environmental Protection (PA DEP) prior to construction are eligible for protections under the PA EGSA. PA DEP has developed a project proposal form for participants and landowners. Each proposal must identify the project participants and landowners, describe the location of the project and the environmental problems that will be addressed, and establish a work plan for the proposed project. The PA DEP evaluates each proposal to determine if the project is capable of reclaiming the land or improving water quality. The PA DEP will also advise participants on any permits that may be required. Once the project is approved, PA DEP will maintain a permanent record of the participants and landowners who are protected under the PA EGSA.