In January 2017, OSMRE renamed the Acid Drainage Technology Initiative (ADTI) to the Mine Drainage Technology Initiative (MDTI) to more accurately reflect the need to address issues associated with mine drainage, all of which may not be acidic. MDTI provides a forum for collaboration and information exchange with the following goals:

• Develop an understanding of acidic and toxic mine drainage (MD) so as to better predict, avoid, monitor, and remediate mine drainage
• Develop innovative solutions to acidic and toxic MD water-quality problems
• Identify, evaluate, and develop “best science” practices to predict acidic and toxic MD prior to mining
• Identify successful remediation practices for existing sources of acidic and toxic MD and describe the best technology for its prevention

History of MDTI

Acid mine drainage (AMD) has been a detrimental by-product of coal mining for many years. At present, acid mine drainage continues to pose a potential problem in some areas, despite improved prediction and prevention techniques.

The MDTI was formed as a partnership of technical experts from industry, state and federal agencies and academia who have joined together to combat the pervasive problem of AMD.

AMD is a long-term water pollution impact of mining in the coal fields of Appalachia and other areas of coal and metal mining. At right is a typical acid mine drainage discharge from an abandoned underground coal mine.

To combat this problem, the MDTI was formed as a partnership of technical experts from industry, state and federal agencies and academia who have joined together to combat AMD and related water-quality problems from mining and seek solutions to them.

MDTI provides a forum for collaboration and information exchange on the following goals:

• Develop innovative solutions to AMD and related water-quality problems
• Identify, evaluate, and develop “best science” practices to predict AMD prior to mining
• Identify successful remediation practices for existing sources of AMD and describe the best technology for AMD prevention
• Work cooperatively to develop understanding and applications of proven and innovative technologies to predict, avoid, monitor, and remediate mine drainage
• Promote transfer of information on mine drainage prediction, monitoring, avoidance and remediation

Continuing and Future Work

Under Title IV and Title V of the Surface Mining Control and Reclamation Act (SMCRA), as amended, OSMRE provides cooperative agreements to develop and demonstrate improved technologies and best science practices in the fields of mining and reclamation.

Recent Projects

• Acid Base Accounting (ABA) for Prediction of Postmining and Reclamation Water Quality
  ABA is an important method for predicting postmining and reclamation water quality and evaluating the potential for production of acid mine drainage. The method, developed in the 1960’s and 1970’s and continuously refined since (Perry, 1998), assesses the potential for the production of acidic drainage at a mine site by balancing the acid-producing and the acid-neutralizing potential of materials at a site to predict the net water quality that can be expected. (Skousen et al., 2002)
  

  The NMLRC has been studying the effectiveness of acid base accounting for predicting postmining and reclamation water quality (Skousen et al., 2002). Overburden analyses, permit maps, and predictions of postmining and reclamation water quality data were collected from regulatory agency permit files from several states in the Appalachian coal region. Data collected from these files was used to calculate mass-weighted acid base accounting for each site. Neutralization potential (NP), maximum potential acidity (MPA) and NP/MPA ratio from each ABA were compared to alkalinity levels in postmining and reclamation water quality data. The results of the ABA analyses were found to be correct in 82% of the cases using the NP/MPA parameter; this indicates that ABA is a good way to predict postmining and reclamation water quality at a mine site (Skousen et al., 2002). More work is planned or is underway to refine this useful analytical tool.

• In-Situ Underground Mine AMD Treatment Technology
  In-situ neutralization is a relatively new concept in the field of passive AMD treatment. The addition of alkaline materials into underground mine voids and ground-water recharge areas may provide an attractive alternative to current treatment practices. These systems require limited land area and, because many of these systems are installed in areas that exclude or limit oxygen, may permit the neutralization of acid without the precipitation of metals in the system. Under this task, three in-situ treatment systems were installed in north-central West Virginia. These sites include a deep mine alkaline injection project, an in-situ limestone portal drain, and ground water alkaline recharge trenches. The performance of these systems with respect to acidity neutralized and metal removed from the discharge is being monitored. The final report on this project is pending.
• Kinetic Test Methods
  MDTI is following up on the recommendations by Geidel et al., (2000) and Perry (2000) to find a consensus on the establishment of kinetic testing protocol for evaluating potentially acid-generating materials. There are several humidity cell methods and numerous leaching column methods that have been used to predict the quality of drainage from coal and metal mines. However, there are currently no standard methods that are widely used and accepted as accurate predictors of coal mine drainage quality by state and federal regulatory agencies or the coal mining industry. Hornberger and Brady (1998, page 7-5) state — "A tremendous amount of kinetic test information now exists, but the variety of test apparatus and procedures in use is so great that it is very difficult to interpret the results and make meaningful comparisons of data from different studies in similar or different lithologic settings[.] *** [I]t should be no wonder that mine operator and consultants new to the subject of AMD prediction would shy away from kinetic tests because they don't know which apparatus or procedure to use, nor how to interpret the results." In order to rectify this problem, OSMRE funded a project to:
  • Develop standard procedures for a humidity cell test and a leaching column test that will meet the U.S. EPA requirements for performance-based measurement systems (PBMS) methods specifications, and
  • Improve existing humidity cell and leaching column test methods by maintaining a carbon dioxide enriched gas environment throughout the test to simulate the partial pressure of CO2 normally found in soils and spoil gas environments. This is needed to optimize carbonate mineral dissolution and the production of significant alkalinity concentrations in ground water, mine drainage discharges, or leachate in laboratory tests used to predict mine drainage quality.
• Selenium Pollution
  Selenium is a naturally occurring widely distributed element, which shows an affinity for sulfide minerals. It combines with metals and non-metals and may form both organic and inorganic compounds. Selenium is the most strongly enriched trace metal in coal, and can occur in several forms in solution. Selenium discharges that exceed water quality standards have been identified in several coal mine watersheds in southern West Virginia. It is suspected that these Se concentrations are the result of leaching of selenium compounds in coal and overburden exposed to oxidizing conditions during mining activities in this region.
  

  OSMRE is currently funding an MDTI cooperative agreement with West Virginia University to determine sorption-desorption parameters for selenite as a function of temperature to iron oxides formed during mine drainage treatment and other common minerals found in acid and alkaline mine drainage impacted waters.

Published Reports

• Prediction of Water Quality at Surface Coal Mines (2000)
  ABA is an important method for predicting postmining and reclamation water quality and evaluating the potential for production of acid mine drainage. The method, developed in the 1960’s and 1970’s and continuously refined since (Perry, 1998), assesses the potential for the production of acidic drainage at a mine site by balancing the acid-producing and the acid-neutralizing potential of materials at a site to predict the net water quality that can be expected. (Skousen et al., 2002)
  

  The NMLRC has been studying the effectiveness of acid base accounting for predicting postmining and reclamation water quality (Skousen et al., 2002). Overburden analyses, permit maps, and predictions of postmining and reclamation water quality data were collected from regulatory agency permit files from several states in the Appalachian coal region. Data collected from these files was used to calculate mass-weighted acid base accounting for each site. Neutralization potential (NP), maximum potential acidity (MPA) and NP/MPA ratio from each ABA were compared to alkalinity levels in postmining and reclamation water quality data. The results of the ABA analyses were found to be correct in 82% of the cases using the NP/MPA parameter; this indicates that ABA is a good way to predict postmining and reclamation water quality at a mine site (Skousen et al., 2002). More work is planned or is underway to refine this useful analytical tool.

• A Handbook of Technologies for Avoidance and Remediation of Acid Mine Drainage (1998)
  The MDTI Coal Mining Sector’s Avoidance/Remediation Working Group prepared this user oriented handbook on AMD Remediation Methods for coal mining in the Appalachian region that includes case studies. It is a compilation of previously conducted AMD remediation technology experiments and technology , including those that did not succeed. The anticipated outcome will be a higher success rate in remediating existing sources of AMD and more cost effective stream cleanup. OSMRE and the National Mining Association provided funding for these publications, which were published by the NMLRC.

  Printed copies of both reports are available. There is a $20.00 fee for each hard copy book requested, in addition to a postage fee. To obtain a printed copy, contact Terry Polce from West Virginia University.

  West Virginia University
  West Virginia Water Resources Institute
  202 NRCCE Building, PO Box 6064
  Morgantown, WV 26506-6064
  Attention: Terry Polce

  Email: Terry.Polce@mail.wvu.edu;
  Phone: (304) 293-2867 x 5450; Fax: (304) 293-7822

FAQs

• What is acid mine drainage?
  AMD or acid rock drainage (ARD), collectively called acid drainage (AD), is acidic water (pH less than 5.0), laden with iron, sulfate and other metals, that forms when geologic strata containing sulfide minerals such as pyrite are exposed to the atmosphere or oxidizing environments. AMD can form from coal mining, both in surface and in underground mines, but AD can also result from metal mining, or under natural conditions where sulfides in geologic materials are encountered in highway construction, and other deep excavations. Iron sulfides common in coal regions are predominately pyrite and marcasite (FeS2), but other metals may be combined with sulfide in the form of chalcopyrite (CuFeS2), covellite (CuS), and arsenopyrite (FeAsS). Pyrite commonly occurs with other metal sulfides, potential causing AD.
• What is the Mine Drainage Technology Initiative?
  To combat the long-term water pollution impacts of mining in the coal fields of Appalachia and other areas of coal and metal mining, the MDTI was formed as a partnership of technical experts from industry, state and federal agencies and academia who have joined together to combat AMD and related water-quality problems from mining and seek solutions to them. There are two major units: a CMS and a Metal Mining Sector (MMS). Working groups in each sector focus on Prediction and Avoidance /Remediation. An Operations Committee provides overall direction.