Evaluating the Performance of a Seepage Barrier Constructed with Coal Combustion Product Grout to Reduce the Loss of Ground Water Seeping

into a Former Coal-Mining Shaft

Nathaniel Warner, Matthew Erbe and Leonard Rafalko, Environmental Resources Management, Inc.; Paul Petzrick, Maryland Power Plant Research Program; and Gary Fuhrman, Western Maryland

Resource Conservation & Development Abstract The Kempton Man Shaft (Man Shaft) project is one of several projects sponsored by the Maryland Department of Natural Resources Power Plant Research Program (PPRP) to demonstrate the beneficial use of coal combustion products (CCPs). The project was funded in part by the US Department of the Interior Office of Surface Mining and designed to demonstrate the replacement of concrete with coal combustion products (CCPs) as the cementitious material in standard geotechnical applications. The 420-foot deep Man Shaft is located in the former Kempton deep coal mine in Kempton, Maryland. The shaft terminates in the Kempton mine pool and contributes to the generation acid mine drainage (AMD) discharging into Laurel Run. Bedrock fractures intercepted by the shaft convey good quality ground water into the shaft and ultimately to the mine pool, where it contributes to the millions of gallons of AMD that discharge into Laurel Run. Exploratory boreholes drilled around the Man Shaft identified horizontal fractures in siltstone bedrock at depths between 124 feet and 137 feet. The seepage of ground water into the Man Shaft from these fractures is estimated to be 45,000 to 145,000 gallons per day. Accordingly, the project objective was to reduce the amount of ground water lost to the mine pool by installing a seepage barrier to a depth of about 160 feet around the shaft using a cementitious grout consisting of local CCPs. The seepage barrier was installed during September through November 2003 by pressure injecting the grout through a series of boreholes surrounding the Man Shaft. The added benefit of the project was the use of the CCPs, which would otherwise have been landfilled. PPRP is collecting data to evaluate the effectiveness of the CCP grout as a seepage barrier to reduce the loss of ground water seeping into the Man Shaft. A combination of potentiometric surface monitoring and dye tracing activities is being used to evaluate the effectiveness of the seepage barrier. Additionally, PPRP is monitoring ground water quality in the Man Shaft and surrounding monitoring wells to determine if the CCP grout is affecting the ground water quality through dissolution. This paper will present the results of the potentiometric surface monitoring and dye tracer testing. Activities were initiated at the Man Shaft in July 2003 to assess hydraulic conditions associated with the water-yielding fractures. The dye tracer study involved the injection of non-toxic fluorescent dye into the on-site wells. The breakthrough of the dye was then monitored in the Man Shaft. The information from the tracer study will be used to supplement the lithologic information obtained from the installation of the wells. A post-CCP grout injection dye tracer study will be performed in the Spring 2004. The results of the dye tracing will be used in a qualitative manner to assess the relative percent reduction in ground water flow from fractures into the Man Shaft as a result of the seepage barrier. The assessment will be performed by comparing dye concentrations observed pre and post-CCP grout injection.

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INTRODUCTION

In 1995, the Maryland Department of Natural Resource Power Plant Research Program (PPRP) and the Maryland Department of the Environment (MDE) Bureau of Mines (BOM) initiated the Western Maryland Coal Combustion by-products (CCP)/Acid Mine Drainage (AMD) Initiative (Petzrick, 1999). The Initiative is a joint effort between private industry, state and federal agencies to demonstrate the beneficial application of CCPs to create a pozzolan-based flowable and environmentally benign grout for placement in underground coal mines to reduce acid formation, prevent subsidence, and restore natural drainage patterns. PPRP selected the Kempton Mine Complex as a candidate mine for the injection of CCP grout to abate millions of gallons per day of AMD that discharge from the Mine Complex into Laurel Run, which is a tributary to the North Branch of the Potomac River (North Branch). The complex consists of nine interconnected abandoned mines, covering a surface area of about 12 square miles (Figure 1). Seven percent of the mines lie in Garret County Maryland, the remaining 93 percent are in West Virginia. Davis Coal & Coke Company (DC&CC) operated the mines from the 1880s to 1950, excavating the Upper Freeport coal seam by room and pillar. As a legacy of these mining operations, acid mine water exists in two mine pools. The larger of the two pools is the Kempton Pool, which contains about 1,100 million gallons of acid water. One of the identified pathways of ground water discharge to the Kempton Pool is the 420-foot deep Kempton Man Shaft for abandoned Mine No. 42 in Kempton, Maryland (Figure 2). The Man Shaft was used for forced air ventilation and elevator access for mine workers. When the mine was active, the Man Shaft had a secondary role of collecting potable water for the Town of Kempton water system. The water was collected in the Man Shaft by a collar and was then pumped to a storage tank above the town or discharged directly to the North Branch. As reported by Burrill (1931) the collar consists of a notch cut into the rock walls of the Man Shaft at a depth of about 178 feet below the top of the shaft (Figure 3). Burrill reported that ground water leakage into the Man Shaft averaged 2,000 gallons over a 20-minute period, which translates into a flow rate of 100 gpm or 144,000 gpd.

As described herein, hydrogeologic testing revealed that good quality ground water was infiltrating into the Man Shaft through fractures below the ground surface. The Man Shaft Project is intended to demonstrate the use of CCPs as a replacement for concrete as a cementatious material in the formation of a pozzolan-based CCP seepage barrier. The seepage barrier is intended to decrease the hydraulic conductivity of the bedrock fractures in the vicinity of the Man Shaft, thereby decreasing the flow of good-quality ground water into the Man Shaft, which eventually reaches the Kempton Pool and discharges as AMD into Laurel Run.

PHYSICAL SETTING

The project area lies above the northeasterly-flowing headwaters of the North Branch, which lies approximately 300 feet southwest of the Man Shaft. Laurel Run is a tributary to the North Branch. The headwater of Laurel Run is located 4,000 feet north of the Man Shaft and receives AMD from the Kempton Mine Complex (Figure 1).

STRATIGRAPHY AND HYDROGEOLOGY

The Kempton Mine Complex is located in the Appalachian Plateaus Physiographic Province in the extreme southwestern corner of Garrett County, Maryland. Bedrock in this region consists primarily of shale, claystone, siltstone and sandstone. Gentle folding in the region has produced a series of elongated anticlines trending approximately N40°E and plunging 2 to 3 degrees to the northeast. In the intervening synclinal basins, coal-bearing strata of Pennsylvanian age are preserved. The Kempton Mine Complex was established to recover coal from the Upper Freeport seam, which is about 4 to 4.5 feet thick throughout most of the mine.

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Drilling logs for boreholes drilled by DC&CC for the Kempton Complex were evaluated to determine the geologic and hydrologic properties of the bedrock surrounding the Man Shaft. In particular, test boring 47, which was drilled within a few feet of the Man Shaft on 11 December 1911, provided stratigraphic information used to design the injection project. Additional geologic information was provided by a geophysical survey of the area by the National Energy and Technology Laboratory. The survey indicates the bedrock between the wetlands and the Man Shaft is possibly fractured and has increased bulk conductivity leading to an increased capacity to transmit water compared to the surrounding rock. In April 2001, four shallow (KMW-1A, KMW-2, KMW-3, and KMW-4) and two deep (KMW-1M and KMW-1D) boreholes were drilled into the bedrock around the Man Shaft (Meiser and Earl, 2001). KMW-1D was installed directly into the mine pool, approximately 420 feet below ground surface (bgs) (Figure 2). These monitoring points provided geologic and water level information in four directions outside of the Man Shaft, and a sampling location in the mine pool. The drilling indicates that the principal fractures providing water to the Man Shaft are located within approximately the upper 120-150 feet of bedrock (Figure 3). Blown yields (i.e., water discharged from the borehole by forcing air down the borehole) from these fractures during drilling were as much as 60 gallons per minute (gpm) of ground water. Ground water level measurements from the monitoring wells around the Man Shaft indicate that ground water flow is towards the shaft. The data obtained from the monitoring wells between August 2001 and January 2002, including ground water gradients, pumping test data, and borehole logs, were used to estimate the discharge of ground water into the Man Shaft via the fractured bedrock. Transmissivity values of 3,700 to 18,000 gallons per day per foot were determined through 1-hour pumping tests conducted at wells KMW-2, KMW-3 and KMW-4. The discharge into the Man Shaft was calculated using the hydraulic gradients, calculated between each monitoring well and the Man Shaft, the transmissivity values for each well, and assuming that the 5-foot thick (i.e., saturated cross

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sectional area) fracture zone identified in the monitoring wells intersected each wall of the Man Shaft. The four discharge rates were then added together to calculate the total discharge rate into the Man Shaft from the fracture zone in the bedrock as 45,000 to 93,000 gallons per day. The range is representative of hydraulic gradients calculated from ground water measurements at the four monitoring wells. This corresponds well to the historical estimation of ground water discharge based on pumping rates from the Burrill, 1931 report.

GROUT FORMULATION

The CCP grout formula for this project was developed through laboratory tests by Hemmings and Associates and field adjustments to produce a grout that had rheological properties capable of penetrating rock fissures, adequate strength for physical support, maintenance of physical and chemical integrity, and stability and compatibility with mine water. The CCPs selected for the project were fluidized bed combustion (FBC) ash and pulverized coal fly ash (PFA) from Dominion Power Company’s North Branch and Mount Storm power plants, respectively, located nearby Kempton, Maryland. Material samples used for characterization proved to be generally representative of normal production at the plants. The initial grout formula was based solely using the North Branch FBC as the lime source. However, the North Branch power plant unexpectedly shut down during grouting, which resulted in the use of FBC material from the AES Warrior Run power plant, in Cumberland, Maryland to complete the project. The final design called for a mix ratio of 50:50 unconditioned FBC to conditioned PFA. The solids contents (Cw) defined as the weight percent of solid material in the wet grout mix ranged from 60 to 65 percent. FIELD IMPLEMENTATION

Coastal Drilling East initiated site preparation and injection borehole drilling in August 2003 and completed the grout injection in November 2003. A total of 78.2 cubic yards of grout were injected into 29 boreholes. The grout used 100 percent mine water pumped from the Kempton Mine Pool through the Man Shaft and 100 percent CCPs.

SITE PREPARATION

Silt fencing was installed to prevent the release of disturbed soils and sediment. A temporary stabilized construction entrance was installed with a gravel surface for vehicle and equipment access to the project area. The stockpile area was properly secured with silt fencing, and underlain by geotextile. The PFA and FBC ash stockpiles were covered as necessary. The control measures were maintained throughout grout injection and site reclamation activities.

DRILLING INJECTION BOREHOLES

The injection boreholes were spaced in two concentric “rings” 5 feet and 10 feet away from the expected outer edge of the Man Shaft cement cover that was installed by BOM during a 1996 surface reclamation project (Figure 4). A total of 14 boreholes were in the inner ring and 15 boreholes in the outer ring. All boreholes were 6-inch diameter with a 6-inch polyvinylchloride casing installed to 20 feet (bgs). The casing was intended to keep the unconsolidated surface material (i.e., gob) from falling into the borehole and to eliminate loss of grout to the overburden. The casing was grouted in place using the CCP grout mix, and on occasion Portland cement was used when a quicker set-up time was required. Injection at each borehole was drilled to at least 10 feet below the water-bearing zone (a minimum depth of 152 feet bgs) using a 6-inch rotary air hammer (Table 1). First water was encountered at 35 to 50 feet bgs, but significant water was encountered at 120 to 140 feet bgs with blown yields from 50 to 100 gpm in that zone, which is consistent with results of prior drilling. The fractures identified while drilling the existing monitoring wells (KMW-1 to KMW-4) were more competent than the fractures encountered during drilling the CCP grout injection points. The rock quality was poor with an estimated rock mass class of Fair (III) to Poor (IV) in the fractured zones based on the US Army Corps of

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Engineers Rock Mass Classification Tables. While drilling, two zones in particular appear to be more fractured. An upper fractured zone in the sandstone between 25 to 45 feet bgs and a heavily weathered zone in the sandy siltstone-shale 120 to 145 feet bgs (Figure 3).

The poor quality of the rock lead to significant cave-ins shortly after drilling and several holes were re-drilled to insert a tremie tube so that the hole could be grouted (Table 1). A more efficient method of keeping the holes open was to insert a 3-inch casing into the hole, past the fracture zone, and then insert the 1.25-inch tremie pipe through the casing. Once the tremie pipe was in place the 3-inch casing was removed and grout injection commenced. The poor quality rock and cave-ins also led to the variation in the drilling and grout sequence. It was necessary to grout and drill several holes out of sequence to ensure that drilling and grouting did not occur at nearby holes.

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GROUT INJECTION

Over 78 cubic yards of grout were injected into 29 boreholes (2.7 cubic yards/hole), with a minimum of 0.94 cubic yards (A-4), and a maximum of 8.01 cubic yards (A-14). In addition to the volume to fill the borehole, there was an average of 1.54 cubic yards of void space (fractures) that CCP grout filled within each borehole. Figure 4 shows the grout injection holes with the amount of grout injected into each hole represented by the relative size of each circle. Two areas outside of the Man Shaft, the north-northeast and southeast, required the most grout. Borehole A-7 was never fully grouted and is believed to be in direct connection with a large void in the bedrock that leads directly to the Man Shaft. Hole A-7 was therefore left open as a monitoring point between the Man Shaft and the seepage barrier. While the engineering design required each borehole to be grouted until the pressure at the top of the hole reached 150 pounds per square inch (psi), field conditions dictated that several boreholes required the termination of pumping at 30 to 40 psi because grout was observed at the surface, an adjacent borehole, or the Man Shaft. Several other boreholes also did not reach the required pumping pressure because of early termination of pumping due to time constraints.

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GROUT PROPERTIES DURING INJECTION

A construction Quality Assurance/Quality Control Plan (CQAP) was prepared and implemented for the duration of grout injection and site restoration. The CQAP established procedures and field tests to ensure grout consistency and replication. Field tests for water content were performed when new shipments of PFA were delivered, and at periodic intervals if the PFA was left on site for any extended period of time. The field tests showed the conditioned PFA material had a range of 24 to 28 percent water content as it was utilized. Flowability (spread) tests were conducted at least once per batch of grout mixed using Provisional Standard Test Method for Flow Consistency of Controlled Low Strength Material (ASTM PS 28-95). The average spread of a 6-inch high by 3-inch diameter cylinder was 9.25-inches by 9.2-inches for the grout mixed with North Branch FBC. The spread was reduced to 6.8-inch by 7.0-inch for grout mixed with Warrior Run FBC material due to the finer particle size and increased viscosity of this material. At least twice per injection hole, grout samples were collected and cast into 6-inch high by 3-inch diameter cylinders for unconfined compressive strength determination. The cylinders were strength tested in the field using a pocket soil penetrometer and then later by Coastal Drilling East. The data show that the grout as prepared in the field for the project was slower to develop and had a lower total strength than the laboratory prepared samples, most likely due to the lower solids content.

PRE AND POST-INJECTION MONITORING

PRECIPITATION DATA

Precipitation measurements from August 2003 through January 2004 were obtained from the National Oceanic and Atmospheric Administration (NOAA) Climatology station located in Davis, West Virginia, approximately 20 miles south of the site. The precipitation data showed that there was a 5 to 6 day lag between precipitation events and subsequent increase in ground water levels in the monitoring wells surrounding the Man Shaft.

WATER LEVEL MONITORING

Ground water levels were monitored in the Man Shaft and four intermediate monitoring wells (KMW-1A, KMW-2, KMW-3 and KMW-4) for one month before, during, and after the installation of the seepage barrier as follows: 1) Manual measurements of depth to water were collected approximately weekly during drilling; and 2) Solinst 3001 LT Leveloggers® were installed approximately 10 feet below the ground water surface, and

were used to record pressure head continuously at 1 hour intervals.

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The data from the Leveloggers® (Figure 5) was used to produce the ground water contour map for August 2003, prior to injection of grout, shown in Figure 6. Based on depth to water measurements and pressure readings collected in August 2003 the potentiometric ground water surface sloped to the southeast. The measurements also indicated that localized hydraulic gradient was directed toward the Man Shaft.

Leveloggers® placed in the Man Shaft and monitoring wells KMW-1A, KMW-2, KMW-3, KMW-4, show little or no increase in water levels after grout injection, with the notable exception of KMW-3. As illustrated in Figure 5, KMW-3 saw a dramatic increase in pressure (and therefore water level) during grouting, followed by a gradual increase in water levels after injection. KMW-1A, KMW-2, and KMW-3 showed increased variability in pressure readings during the drilling and injection phases resulting from the drilling and grouting processes. KMW-4 showed little or no change throughout the entire monitoring period. After completion of the grout injection phase, variability in the transducer readings decreased significantly. The corresponding ground water elevation maps based on the data from the Leveloggers® for pre- during- and post-grout injection are shown in Figure 6. The pressure transducers in monitoring wells KMW-1A, KMW-2, KMW-3, KMW-4 and the Man Shaft will continue to be monitored for indications of a water level rise compared to pre-injection levels.

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DYE TRACER TEST

A second measure to qualitatively evaluate the effectiveness of the CCP seepage barrier for reducing the amount of ground water lost to the Man Shaft was through the performance of a fluorescein dye tracer study. Prior to performing the test, samples were collected from the airshaft, borehole, Man Shaft, and coal shaft to establish baseline conditions. Samples taken from the Man Shaft from 7 July 2003 to 22 July 2003 showed background flourescein concentrations ranging from 0.010 ppb to 0.018 ppb. To meet laboratory protocol procedures flourescein needs to be detected in the water sample at a concentration 10 times above the background levels (i.e. 0.1 ppb). PRE-INJECTION On 28 July 2003, known mass loads of fluorescein were added to monitoring wells KMW-1A (1/16 pound), KMW-2 (9/16 pound), KMW-3 (1/16 pound) and KMW-4 (5/16 pound) at 120 feet below the top of each casing. The mass loads were determined based on the relative transmissivities for each well. The dye was injected under positive pressure by adding six gallons of distilled water to the top of each well. Water samples were then collected from within the Man Shaft at a depth corresponding with the deep fracture zone,

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approximately 140 feet bgs, to provide a snapshot of the quantity of dye in the system. Absorbent activated charcoal packets were also added to the Man Shaft and removed at specified intervals after dye injection. The charcoal packets were used to measure the cumulative amount of dye moving through the system. The charcoal packets also provided lower detection limits than the water samples. The flourescein dye was detected in the water sample collected from the Man Shaft at a concentration of 0.5 ppb one day after dye injection, then increased to a maximum concentration of 10.6 ppb after 14 days (Figure 7). The concentrations in the Man Shaft returned to background levels (below 0.1 ppb) 102 days after dye injection.

POST-INJECTION The results of the pre-grout injection dye tracer test were compared to the results of a second dye tracer test that was initiated on 12 April 2004, after completion of the grout setup, for positive signs that the CCP seepage barrier reduced hydraulic conductivity and ground water flow into the Man Shaft. The second dye tracer test was conducted following the same procedures and with the same dye quantities that were used in the pre-grout injection test. Comparison of the pre- and post-grout injection results did not indicate a quantifiable delay in the arrival time or reduction in total dye mass following installation of the seepage barrier (Figure 8). One possible explanation for this is that the rock encountered around the Man Shaft was much more fractured than previously believed and these fractures proved to be too unstable and too well connected to the Man Shaft to grout properly.

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WATER QUALITY MONITORING

Pre and post injection ground water quality data were collected to determine if the CCP grout affected ground water chemistry. To date, seventeen pre-injection and three post-injection rounds of water quality samples were collected at monitoring locations KMW-1A, KMW-2, KMW-3, KMW-4 and the Man Shaft. These first quarter water quality results are summarized in Table 2. Notably, there have been no apparent changes in trace metal concentrations. General ground water quality parameters have shown a slight decrease in pH and alkalinity. There have been no significant change in calcium or sulfate concentrations indicating competent grout curing.

Table 2. Water Quality Data Comparison For Kempton Manshaft and Monitoring Wells Pre- and Post-CCP Grout Injection (3 events).

LocationParameter Units MIn Max Average MIn Max Average MIn Max Average MIn Max Average MIn Max Average MIn Max Average

Major IonsCalcium (mg/L) 20.5 58.4 37.29 22 34 29.40 19.8 60.6 36.48 31 36 33.67 16.5 50.1 32.58 40 49 44.67Iron (mg/L) 0.03 0.9 0.27 0.0 2.5 0.64 0.03 1.14 0.17 0.05 0.79 0.30 0.03 0.56 0.17 0.07 2.8 1.22Magnesium (mg/L) 2.4 21.6 8.45 4.1 7.2 5.60 2.9 21.3 8.61 7.3 9 8.03 1.7 304.3 23.92 9.1 9.7 9.33Potassium 1.06 1.93 1.48 0.9 1.4 1.22 0.7 1.98 1.15 0.7 1.1 0.91 1.22 2.83 2.24 1.6 1.9 1.73Sodium 4.5 180.1 25.74 1.6 4.6 3.20 3.5 208.2 37.70 2.4 2.7 2.57 12.6 224.6 57.19 16 19 17.7Chloride 0.7 1.2 0.85 5 5 5.00 0.7 1 0.92 5 5 5.00 0.5 0.6 0.59 5 5 5Sulfates (mg/L) 12.9 48.6 30.94 40 54 45.72 10.4 42.4 28.78 37 41.3 39.10 6.7 20.8 15.77 54.7 75 66.9

Trace MetalsAluminum (mg/L) 0.07 0.38 0.12 0.07 1.40 0.40 0.1 0.1 0.10 0.07 0.56 0.27 0.1 0.1 0.10 0.07 0.34 0.17Arsenic (mg/L) 0.0004 0.0004 0.00 0.005 0.014 0.007 0.0001 0.0003 0.00 0.005 0.012 0.007 0.0006 0.0012 0.00 0.005 0.008 0.006Barium (mg/L) 0.16 0.16 0.16 0.038 0.680 0.194 0.0545 0.0635 0.06 0.07 0.64 0.27 0.18 0.22 0.21 0.082 0.13 0.11Beryllium (mg/L) 0.00005 0.00005 0.00 0.002 0.005 0.004 0.00005 0.00005 0.00 0.005 0.005 0.005 0.00005 0.00005 0.00 0.005 0.005 0.005Cadmium 0.03 0.03 0.03 0.001 0.005 0.004 0.03 0.03 0.03 0.0005 0.005 0.004 0.03 0.03 0.03 0.0005 0.005 0.004Chromium 0.03 0.03 0.03 0.002 0.029 0.009 0.03 0.03 0.03 0.002 0.035 0.014 0.03 0.08 0.03 0.002 0.005 0.004Copper 0.03 0.03 0.03 0.005 0.050 0.015 0.03 0.03 0.03 0.005 0.05 0.020 0.03 0.03 0.03 0.005 0.05 0.020Lead 0.03 1.86 0.30 0.005 0.011 0.006 0.03 0.5 0.14 0.005 0.005 0.005 0.03 0.41 0.10 0.001 0.005 0.004Manganese (mg/L) 0.03 0.64 0.20 0.005 0.880 0.301 0.03 0.4 0.07 0.021 0.28 0.13 0.03 0.45 0.08 0.23 0.35 0.27Nickel 0.03 0.09 0.04 0.005 0.018 0.008 0.03 0.06 0.04 0.005 0.012 0.007 0.03 0.12 0.04 0.005 0.005 0.005Selenium (mg/L) 0.0001 0.0001 0.00 0.005 0.005 0.005 0.0001 0.0003 0.00 0.005 0.005 0.005 0 0.0001 0.00 0.005 0.005 0.005Zinc (mg/L) 0.02 0.04 0.03 0.012 0.127 0.06 0.03 0.04 0.03 0.006 0.114 0.057 0.03 0.04 0.03 0.007 0.05 0.023

Other ParameterspH pH units 6 7.85 6.66 6.08 6.64 6.41 6.52 8.26 6.88 6.04 7 6.58 7.1 8.27 7.64 6.72 6.9 6.79Acidity (mg/L) 0 0 0.00 12 240 61 0 0 0 10 16 12 0 0 0 8 10 9Alkalinity 1 (mg/L) 46.7 155.3 90.90 32 72 48 51.2 144.4 89 70 72 71 116.9 169 139 106 112 110Conductivity 2 µohms/cm 177 320 246 153 220 191 170 320 230 240 243 242 198 359 278 190 340 286Dissolved Solids (mg/L) 86 162 138 140 210 160 116 168 140 160 180 170 137 184 163 240 250 247

LocationParameter Units MIn Max Average MIn Max Average MIn Max Average MIn Max Average MIn Max Average MIn Max Average

Major IonsCalcium (mg/L) 27.3 62.1 41.48 32 37 34.33 32 103.7 79.03 65 65 65 33.5 79.6 51.58 32 53 40.33Iron (mg/L) 0.02 2.04 0.33 0.05 0.12 0.09 19.9 82 62.07 0.9 50 17.87 0.03 1.74 0.218 0.19 100 36.93Magnesium (mg/L) 2.2 24.6 8.50 6.3 6.6 6.5 12.6 46.2 23.79 16 21 17.67 3.6 21.4 9.29 7.5 12 9.3Potassium 1.58 2.9 2.08 1.5 1.9 1.7 2.7 4.63 3.68 2.5 2.8 2.67 1.04 2.46 1.96 0.98 1.8 1.39Sodium 11.99 196.3 43.96 14 15 14.7 10.2 252.3 44.37 7.5 110 42.2 9.1 167.3 39.12 5.2 8.7 6.53Chloride 0 1 0.52 5 5 5 0.6 1.9 1.45 5 5 5 0.6 0.9 0.81 5 5 5Sulfates (mg/L) 3.2 22.3 10.69 17 19.8 18.6 30.6 416 317.65 110 399 282 12.9 30.2 21.73 35 52 42

Trace MetalsAluminum (mg/L) 0.1 0.1 0.10 0.022 0.097 0.050 0.1 4.7 0.52 0.21 16 5.9 0.01 0.1 0.094 0.08 0.49 0.217Arsenic (mg/L) 0.0005 0.0027 0.00 0.005 0.005 0.005 0.00112 0.0035 0.00 0.005 0.005 0.005 0.0001 0.0010 0.0004 0.005 0.016 0.009Barium (mg/L) 0.082 0.227 0.15 0.137 0.2 0.17 0.08 0.11 0.09 0.08 0.098 0.09 0.0620 0.1000 0.0873 0.057 0.14 0.089Beryllium (mg/L) 0.00005 0.0008 0.00 0.005 0.005 0.005 0.0003 0.0009 0.00 0.002 0.005 0.004 0.00005 0.00005 0.00005 0.005 0.005 0.005Cadmium 0.03 0.03 0.03 0.0005 0.005 0.004 0.03 0.03 0.03 0.0005 0.005 0.0035 0.03 0.03 0.03 0.0005 0.005 0.004Chromium 0.03 0.09 0.04 0.002 0.005 0.004 0.03 0.03 0.03 0.004 0.005 0.005 0.03 0.03 0.03 0.002 0.005 0.004Copper 0.03 0.03 0.03 0.005 0.05 0.020 0.03 0.03 0.03 0.005 0.05 0.020 0.03 0.03 0.03 0.005 0.05 0.020Lead 0.03 0.32 0.08 0.005 0.005 0.005 0.03 0.54 0.20 0.005 0.005 0.005 0.03 0.3 0.09 0.005 0.005 0.005Manganese (mg/L) 0.03 0.54 0.12 0.13 6.3 2.21 0.98 2.41 1.82 0.8 1.7 1.2 0.03 0.49 0.13 0.43 1.2 0.8Nickel 0.03 0.03 0.03 0.005 0.005 0.005 0.03 0.19 0.09 0.05 0.19 0.098 0.03 0.09 0.04 0.005 0.005 0.005Selenium (mg/L) 0.0001 0.0001 0.00 0.005 0.005 0.005 0.0001 0.08 0.02 0.005 0.005 0.005 0.0001 0.0002 0.0001 0.005 0.005 0.005Zinc (mg/L) 0.03 0.04 0.03 0.005 0.05 0.020 0.03 0.6 0.22 0.12 0.47 0.24 0.03 0.03 0.03 0.005 0.05 0.024

Other ParameterspH pH units 6.9 8.1 7.56 7.18 7.3 7.24 5.51 7.9 6.31 5.39 6.6 6.15 6.8 8.17 7.43 6.28 6.86 6.62Acidity (mg/L) 0 0 0 10 18 13 0 140.8 96 40 146 97 0 0 0 10 18 13Alkalinity 1 (mg/L) 14.04 141.8 127 116 120 118 7.4 66 45 10 66 36 122 156.9 148 88 92 90Conductivity 2 µohms/cm 178 345 264 267 275 271 92 1098 847 516 562 542 212 400 293 249 282 267Dissolved Solids (mg/L) 123 162 147 190 200 197 74 752 603 350 450 410 1.83 190 165 170 190 180

KMW1A Statistics KMW1A StatisticsPost InjectionPost Injection

KMW2 Statistics KMW2 Statistics KMW1D Statistics KMW1D Statistics

Pre Injection Pre Injection Pre Injection

Pre Injection Post Injection

KMW3 StatisticsManshaft Statistics Manshaft Statistics KMW4 Statistics KMW4 StatisticsPost InjectionPost InjectionPost Injection

Pre Injection Pre Injection

KMW3 Statistics

CONCLUSIONS The Kempton Man Shaft Project has demonstrated that CCPs can be used beneficially in place of traditional concrete to form a grout that can be mixed and injected into bedrock fractures. Unconditioned FBC and conditioned PFA material was delivered to the site and used for grout formation. Although the materials were stored on textile mats and covered with plastic sheeting to keep away the elements, improved protection of the materials from precipitation should be considered for similar projects. The materials were easily handled and mixed by a work crew using standard cement grouting equipment, but care should be taken to ensure that the equipment is capable of pumping a thicker grout that may be determined by laboratory testing. Post-injection water quality monitoring shows no adverse impact to ground water quality. Notably, pre and post-injection ground water concentrations of trace metals were comparable. The water quality data also show that the grout remains intact.

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Initial monitoring results indicate that the CCP grout seepage barrier was unsuccessful in reducing the flow of ground water into the Man Shaft. The dye tracer study and ground water level monitoring indicate no substantial flow reduction. This result is attributed to bedrock around the Man Shaft being more highly fractured than previously believed based on pre-injection drilling. The rock encountered around the Man Shaft was significantly more fractured than previously believed. It is possible that these fractures are too unstable and too well connected to the Man Shaft to grout properly. PPRP plans to continue post-injection monitoring of water quality and water levels. In addition, PPRP plans to core between the injection boreholes to collect grout samples for visual inspection and possible physical testing.

REFERENCES

Burrill H., 1931, Report on the Ring Pump, Man Hoist Shaft, Mine 42: Source of Water Supply for the Town of Kempton, MD: Dated: 21 October 1931. Hemmings R., Petzrick P., Sherwell J., and Cornelius B., 2003, Development of CCP Grouts for Mine Reclamation in Western Maryland: 15th International Symposium on Management & Use of Coal Combustion Products (CCPs), St. Petersburg, FL Jan. 27-30, 2003. Meiser and Earl, 2001, Letter to Mrs. Tammy Davis, Department of Geology, Frostburg State University: Dated: 29 August 2001. Petzrick P., 1999, The Maryland Coal Combustion By-Product/Acid Mine Drainage Partnership: in 1999 International Ash Utilization Symposium, Lexington, Kentucky, Oct. 18-20, 1999, Paper 75.