West Branch Harble Griffith 319 Reclamation Project Overview
||This project will address acid mine drainage (AMD) originating from an un-reclaimed ridge top surface mine along Harble Griffith Road in southeastern Hocking County. The project site is a source of AMD that drains into the headwaters of the West Branch of Raccoon Creek. West Branch is considered a priority for restoration by the Raccoon Creek Partnership and is identified as a priority AMD site in the state endorsed Raccoon Creek Headwaters to Above Hewett Fork Watershed Action Plan (2008). The Harble Griffith Road project site is the first step in addressing one of many sources of AMD in the West Branch watershed to restore this creek to attain its WWH designation and to improve water quality in the Raccoon Creek Headwaters.
|The proposed project consists of approximately 29 acres of abandoned (pre 1977 Surface Mining Control and Reclamation Act (SMCRA)) coal mine spoil located east of Harble Griffith Road. The property is currently owned by two separate landowners: Bailey and Payne. The Bailey area is 13 acres and to the north of the Payne area. It contains two large surface water pits (ponds) that hold approximately 1.5 million gallons of AMD water. The Payne area is 16 acres of spoil. It contains one pit (600,000 gallons of AMD water) and has a “low” wall exposed where surface mining ceased. Due to poor surface water drainage throughout the project site most precipitation is directed inward to remnant ponds left by surface mining. These pits increase contact time with water and spoil and increase AMD generation. Drainage off the site is mostly from groundwater seepage from the pits into the spoil banks and then as seepage from the hillside along the coal pit floor. Typical water quality in the pits is pH between 2 – 3 and aluminum concentrations between 10 and 60 mg/l. Aluminum is the dominant AMD metal present, likely due to the large presence of shales and clays in the spoil (see photo below). Iron concentrations are typically less than 1 mg/l. Acid and metal loads have been measured from the three tributaries draining the site during high and low flow scenarios. Combined acid loads from the three tributaries are approximately 326 lbs/day, aluminum loads of 51 lbs/day, and iron loads of 2 lbs/day.
|Pre Construction Sampling
||Summer 2010 - Summer 2011
||May 4th, 2011 on site
|Project Bid Opening
||May 18th, 2011 Columbus
|Pre Construction Tour
||July 20th, 2011
|Post Construction Sampling
||Fall 2011 - Fall 2012
|Post Construction Tour
Due to the geology of the area (i.e. lack of limestone), minimal buffering capacity exists in West Branch and AMD seeps have a large impact on water quality in West Branch. Data from West Branch indicate elevated concentrations of acidity, aluminum, manganese, and a lower pH downstream of the project area. The highest level of net-acidity (acidity – alkalinity) in West Branch downstream of the project area was 27 mg/l in 2008. This is 47 mg/l below the net-alkalinity target of 20 mg/l established in the 2004 Upper Basin of Raccoon Creek TMDL. Aluminum concentrations range from 0.87 – 2.74 mg/l, well above the USEPA continuous criterion of 0.087 mg/l. Iron concentrations are currently below the 1.0 mg/l USEPA criterion. AMD from the project site (and additional abandoned mine sites in the watershed) are seasonal and episodic with precipitation and thus acid and metal loads are higher in wet seasons (Fall to Spring). IBI scores from Ohio EPA in 2008 show degraded fish populations at RM 4.1 (downstream site) with a score of 20 (only 4 fish species present). Upstream at RM 5.7 an IBI score of 38 was recorded. Further downstream at RM 0.2 on West Branch an IBI of 30 was recorded in 2005 indicating some recovery downstream as non-AMD tributaries (i.e. Honey Fork) dilute AMD.
Source control of AMD is always the highest priority and has the most long term benefits for water quality. This project site is well suited for basic mine land reclamation practices and source control. Reclamation techniques will be used that will provide long term water quality impacts with minimal to no maintenance and are proven in the mining industry. Reclamation techniques to be implemented include: re-grading, selective handling and placement of the AMD generating spoil, re-soiling, and establishing vegetation. Approximately 2.3 million gallons of AMD is stored in ponds on the site, which will be drained and filled. The grading plan will incorporate steep slopes to encourage surface water run-off. Mine spoil will be tested for acid-base accounting and the more acidic spoil will be selectively handled and placed in the “highest and driest” locations on site. This practice limits the amount and duration of groundwater contact with the more acidic spoil and thus reduces AMD generation. Water quality of the site (low iron) and relief make open limestone channels well suited as a treatment BMP. Both the Bailey and Payne project areas will incorporate limestone channels for residual AMD treatment and channel stabilization in the drainages off the reclamation areas, 800 and 900 linear feet respectively. Limestone channels, if placed in grades above 10% are effective at neutralizing AMD. In addition, iron hydroxides are main cause of limestone channel failures because of coating. In this case, limestone channels will be placed in grades above 10% and will contact water with very low iron concentrations. The shallow sediment pond/wetland will be approximately 20,000 square feet. This will reduce sediment loads and metal loads into West Branch. The total cost of construction is estimated at $1,117,950.
A final engineering design will be completed by the Ohio Department of Natural Resources Division of Mineral Resources Management (DMRM) by December of 2010. Preliminary concept designs for both project areas are included in the links below.
Bailey Property Concept
Payne Property Concept
Pre-construction monitoring will begin one year prior to construction to establish baseline conditions in West Branch and pre-construction loads will be determined. Post-construction monitoring will begin after the six month review and maintenance period to measure load reductions from implementation of the project.