The purpose of this study was to conduct a field review to collect data and assess certain surface effects resulting from a full extraction underground (longwall) mining operation. The Field Office initiated this study as part of its 1999 Annual Workplan, in part to fulfill oversight requirements to evaluate off-site impacts and reclamation success. Also, citizen’s groups had expressed concerns about the impacts of full extraction coal mining on environmental resources, including streams, and springs, as well as manmade structures such as roads and bridges. The study was not designed to evaluate impacts to residential structures and personal water supplies. Also, the scope of this initial study of surface effects did not include an assessment of impacts on biological resources resulting from full extraction mining.

The study was accomplished with the assistance of staff from OSM’s Appalachian Regional Office, the McMurray Office of the Pennsylvania Department of Environmental Protection (PADEP), and Consolidation Coal Company (CONSOL). The Field Office, with input from PADEP and CONSOL, selected an area over the Bailey Mine for monitoring. See Attachments A and B for location. Two longwall panels were selected, and the evaluation team established monitoring points and began a monthly schedule of visits. The study began in April, 1999, and continued through March, 2000. A copy of the workplan is included as Attachment C.

The study team made monthly visits to the study area from April, 1999 through March, 2000, and collected data from spring and stream monitoring locations. Observations were also made regarding potential surface deformations including land cracks, and changes in topography. Roads and bridges were monitored to determine if subsidence related damage was occurring. It should be noted that the time period of water quantity sampling included a period of region-wide drought that undoubtedly impacted the study data. In addition, there was no baseline information available regarding spring and stream flow prior to the study period; therefore, any seasonal variations unrelated to mining could not be factored into the analysis. The following findings were made based on evaluation data from the entire sampling period. The study team concludes that the followings findings are unrelated to seasonal precipitation variations.

Side hill springs identified and monitored in advance of the passage of the longwall operation all went dry in close proximity to the date of undermining. None of the springs in the study had returned to flow conditions by the end of the data collection period.

One new spring developed in the ditch line of Fleming Hollow Road after mining had passed. This spring was at lower elevation than nearby up-slope springs that had ceased flowing. The new spring was within 10 feet vertical elevation of an unnamed tributary to Beham Run.

One low-flow spring in a bottomland field next to Beham Run, had a substantial increase in flow after mining had passed through. This resulted in expansion of a wet area in a cultivated field.

Several in-stream monitoring points for Beham Run and the unnamed tributary were established and monitored on a monthly basis in advance of and after undermining. All these points had a decrease in water flow during mining, followed by a return to near premining levels by the Spring of 2000. Because of the drought conditions, which started in the Summer of 1999 and ended in the Fall of 1999, the study team was unable to attribute the decrease in water flow at every monitoring point solely to the impact of mining. However, analysis of flow data between individual monitoring points where mining occurred after the end of the drought conditions, did document an immediate and significant, but short-term, loss of water coincident to the passage of the underground mining operation. The term significant is used to describe a section of stream that changed from a net gain in water between the monitoring points, to a net loss of water between the same points. Short term is defined as lasting only a few months. Long term is defined as lasting for a year or longer. At the end of the study period, stream flow at all monitoring stations had returned to premining levels, within the margin of error for the sampling techniques.

The team was advised by local residents that sections of Beham Run did stop flowing during seasonal dry conditions. This condition would classify those sections of the steam as intermittent under the definition at 30 CFR 701.5, as opposed to perennial, which is defined as continuously flowing during all of the calendar year. However, the team observed an abundance of aquatic life in both streams, including small fish, crayfish, and salamanders, that suggests surface or subsurface flow most of the year, and the likelihood of pools of water during drought conditions where aquatic life can find habitat until surface stream flow is returned.

Beham Run makes a perpendicular crossing of the gateway (the area subject to room and pillar mining to allow movement of air, coal and personnel) between longwall panels 5E and 6E. The team did not observe impacts to the physical or flow characteristics of Beham Run at the gateway; however, the normal variation in stream flow over the study period made identification of any mining-related impacts difficult.

Only very minor impacts were noted to road surfaces and bridge abutments during the study. The team conducted monthly visual observations of the gravel roads and culvert bridges in the study area. Very minor cracks in the road surface of Fleming Hollow Road near the crossing of the tributary were noted in one cycle, but were gone by the next. No other changes in road surfaces or bridge abutments were noted by the team. Local residents, however, advised of some minor cracking and heaving in a section of Clovis ridge Road; and a spring, which developed after mining, caused moisture related problems on the road in Fleming Hollow. Both of these problems were corrected by the Township.

The team monitored utility poles and lines to assess the impacts of land surface subsidence and deformation. While several poles appeared, to the team, to be leaning as a result of subsidence, attempts to measure any change were inconclusive. However, no conditions were observed that would constitute safety hazards, or threaten disruption of telephone or electric service.

The team monitored a series of fractures in the shale bedrock in an unnamed tributary to determine surface movement. No change in the pattern of cracking, or the size of the cracks was detected during the undermining process.

The team observed a series of subsidence related surface land cracks at the top of a ridge in a pasture, and wooded area. In places, the cracks were wide and deep enough to present safety issues to people, pets and livestock. The coal company was monitoring the condition. One property owner showed the team where subsidence had changed the surface characteristics of his land to the extent that he could no longer use equipment to keep brush cleared. The team did not have any pre-mining information regarding this property and was unable to verify the claims. The property owner was in discussions with the company regarding this issue and the outcome is unknown. No other changes in the land surfaces were noted.

The impacts observed during this study, including land surface cracks, loss of flow in side hill springs, formation of new springs at lower elevations, temporary diminution in stream flow, and increase in wet areas adjacent to streams, are typical of impacts known to be associated with longwall mining operations.

Changes to stream gradient, and flow conditions in the study area could not be documented during the study period to the extent needed to allow in-depth stream impact analysis.

The drought conditions significantly affected observations, and particularly impacted the two streams monitored in the study area since they were not were not perennial streams. Because of these conditions, the lack of observed impacts to water resources is not a definitive indicator regarding the extent of surface effects from full extraction mining on water resources.

Additional study is needed regarding the impact of longwall mining operations on water resources, including changes in flow, changes in the physical characteristics of streams, and impacts on biological resources.

Further study is also recommended regarding the loss of side hill springs. Loss of such springs potentially impacts land use and the habitats of wet zone plant and animal communities.

Surface subsidence from underground mining may impact land forms, streams, water supplies, public utilities, roads, bridges and surface structures, including private homes. These impacts range from mild to severe and from short to long-term.

The common underground mining methods vary in the extent of coal extracted. Conventional underground mining usually involves some type of room and pillar mining. In more recent years, another approach known as longwall mining, has become the highest extraction methodology and is now the most common and most efficient type of underground coal mining. In this method, large sections of the coal seam, called panels, (The study panels, for example, were 1,000 feet wide and 7,500 feet long.) are completely removed. In order to facilitate ventilation of the mine and transportation of the coal, mining equipment and personnel; the areas surrounding the panel (support areas) are first mined using the "room and pillar" method. Longwall mining machines are then moved in and set up to remove the coal panel. High extraction mining results in what is now termed "planned subsidence," in which the majority of the surface subsidence takes place within a relatively short period after the mining.

The technology associated with planned subsidence, allows predictions to be made of the timing, degree and severity of surface impacts; and measures can be taken, by the coal company, to minimize and mitigate expected damages. Room and pillar mining, the other type of underground coal mining employed extensively in Pennsylvania, does not remove the entire seam of coal as does longwall mining. The room and pillar method leaves surface support in the form of coal pillars. These pillars, however, are frequently removed in subsequent mining operations; or, if left in place, are subject to deterioration and breakdown over time. Historically, surface subsidence resulting from room and pillar mining has been unpredictable, and may occur decades after mining when the mining company is no longer available to repair or compensate for damages.

The short-term effects of high extraction mining on structures and water supplies are becoming well documented, with new information becoming available on a continuous basis. However, the long-term environmental effects are still being assessed. There is a growing interest in studying the impacts that this method of mining is having on water resources, forest growth, and plant and animal communities. Over the next few years additional studies will respond to this area of concern. For example, PADEP has contracted for technical studies regarding effects of longwall mining on forest lands, and wetlands created by this type of mining. The paper "The Use of GPS and GIS in Documenting Subsidence Impacts from Longwall Mining" (Attachment D), which was an outgrowth of this review, documents several hydrologic studies that have been completed regarding the short and long-term impacts of high extraction mining on streams and springs.

The following analysis and discussion is taken in large part from the paper titled, "The Use of GPS and GIS in Documenting Impacts from Longwall Mining" written by Lois Uranowski and Thomas Mastrorocco. This paper was an outgrowth of the subject study, and the site monitoring data is the same for both reports.

Seven monitoring points were utilized to determine the effect of advancing longwall panels had on flow in the two streams of the study area. Four monitoring points were located along a tributary of Beham Run (SW 1, 3, 4, and 5) that flows perpendicular to the longwall panels. SW denotes a surface water monitoring location. Two monitoring points were located along the unnamed tributary of Beham Run (SW 6 and 2) that flows about parallel to and under panel 6. One monitoring point (SW 7) was located in Beham Run upstream and outside the angle of draw and the potential mine subsidence area. This point was used as a control. The sampling points locations is shown in Attachment E. All stream flow data is presented in Attachment F.

The drought of 1999 impeded the study team from determining impacts on stream flow for some of the monitoring points. Also, stream flow monitoring data was unavailable for the time period preceding the study, thereby eliminating the ability to place the study findings in the context of the long term flow characteristics of the streams. Flow rates were affected by the drought conditions during three of the 12 sample dates. During the drought conditions June through September 1999, mining progressed under monitoring points SW 3, SW4, and SW5, precluding the quantification of the effects of longwall mining at these stream locations. As a note, in addition to drought conditions, all samples were subject to weather events, and recent rainfall or snow melt could exaggerate flow conditions, or mask mining related losses. Nonetheless, we believe the following observations are valid mining related results.

Flow rates collected from November 1999 to March 2000 can be used to determine effects of longwall mining on stream flow at monitoring points SW6 and the downstream SW2 on the unnamed tributary. Prior to mining, there was an average net gain in flow between these two points of about 21%. After mining passed under SW 6 in October1999, there was a 97% loss of flow between these two points in the November 1999 sampling. However, in the January 2000, sample there was again a net gain of almost 17%, and at the end of the sampling period in March 2000, there was a net gain of 40% in flow between these two points. Premining flow rates were collected in April and May 1999, prior to drought conditions. SW6 and SW2 are monitoring points on the tributary to Beham Run.

A similar comparison can be made on Beham Run between SW7 (the control point outside mining impact), and the first downstream point SW1. The May 1999 premining sample showed an 11% gain between these two points. December, 1999 post mining monitoring showed a 51% flow loss. However, January, 2000 monitoring showed flow had returned to a net gain of 10%, and the final sample in March 2000, showed a 34% gain.

Seven springs were monitored during the study period. Five springs were identified at the initiation of field work, with one outside the mining area. Two springs developed during the monitoring period and were added to the monitoring schedule. Five springs ceased flow shortly after being undermined, although one exhibited a temporary increase in flow before ceasing.

The spring (SP5) being monitored outside of the mining area showed a flow that fluctuated between .1 gpm and 20gpm, with the .1gpm in July and August 1999, and the 20gpm in January 2000.

Two new springs developed after mining had passed under the area. Both springs were at lower elevation than those that ceased. One spring that developed along Fleming Hollow Road was initially recorded with a flow rate of about 5.6 gpm. Over the next five months, that rate increased to 21gpm. The other new spring was actually two springs within 100 feet of each other. The springs were first noted in September, 1999 as small seeps with minimal flow. These flows are within 10 vertical feet elevation of Beham Run. Beginning in the January 2000 cycle, the combined flow was estimated at 3gpm, and that flow fluctuated over the next two months from an unmeasurable flow to 10 gpm. These springs flowed into a cultivated field adjacent to Beham Run, and created some ponding in the field.

The cessation of flow in the upslope springs, and the formation of new lower elevation springs is indicative of fracturing of the confining rock formations which supports the upslope springs. Subsidence from the passage of the longwall panel may have caused fracturing of this confining layer. This increased hydraulic conductivity may have drained the upper reaches of the ground water causing a lowering of the localized ground water table. The flow reestablished itself at a lower elevation.

These findings regarding stream flow and springs are consistent with other studies as referenced in the attached report.

The Field Office initiated this study as part of its 1999 Annual Workplan. The study was selected to carry out OSM’s oversight requirement that Field Office’s evaluate off-site impacts and reclamation success. The Field Office also had received concerns from citizens groups during public outreach on the proposed workplan. The study was completed under the 2000 Annual Workplan. The study plan was developed, and preliminary meetings were held with PADEP, and with the Pennsylvania Coal Association (PCA) to discuss the objectives of the study, types of data that would be collected, and participation. PADEP offered to include a staff member for the team. The workplan, which is Attachment C, initially included several elements that were subsequently dropped from the study. Those include a review of the regulatory framework of Pennsylvania and Federal laws to determine protections given to surface features; a review of permit files; and a review of monitoring efforts by PADEP and the mining company and their responses to citizen complaints. It was decided that these activities were best addressed through OSM’s program oversight activities, and that the subject study should focus on data collection and impact analysis. As a result of the meeting with PCA, CONSOL officials were consulted, and suggested the use of Panels 5E and 6E of the Bailey Mine in the southwest corner of Washington County. This mine is extracting the Pittsburgh Coal seam that averages about 6.5 feet in this area. Extraction of the coal seam would produce a surface subsidence between 2.5 and 4.5 feet, with the most subsidence occurring in the center of the panel, and the least near the gateways. These panels were suggested because the mining schedule matched the time frame of the study, the presence of two streams and roads above substantial portions of the panels, and the ease of access. CONSOL provided digitized maps of the mine, and surface features, and locations of the face of the longwall operation at the time of each monitoring visit. CONSOL also provided a list of surface property owners. The only concern noted with this panel was that the depth to mining ranged from 560 feet in the valleys to 680 feet on the ridges. This was deeper than initially contemplated, however, other favorable factors outweighed this disadvantage.

The two panels are in a rural area of the county. Only a few structures were within the study area. The geography of the study area consists of moderately to steeply sloping ridges with narrow valley bottoms. The slopes and much of the stream bottoms are heavily wooded with mature trees, shrubs and weedy vegetation. There are some cleared bottom lands that were being farmed for corn. The ridge tops are in pasture land, as are some of the slopes. Beham Run, and an unnamed tributary flow above the panels. These streams develop areas of low or no flow during periods of drought, and have gravel and shale bottoms, with occasional exposed bed rock, and a series of shallow pools and riffles.

The field study team was established, and consisted of two staff from the Harrisburg Field Office including a hydrologist, and a program specialist with forestry education, one staff with a geology background from the Johnstown Area Office, a physical scientist from the Appalachian Regional Office, and a physical scientist from PADEP’s McMurray Office. OSM’s Appalachian Regional Coordinating Center (ARCC) also provided computer support to assist in GIS and mapping activities.

The team began monthly field work in April 1999, establishing monitoring points, and identifying springs. One property owner was contacted on site, and located two side hill springs that he was already monitoring because of concern that mining would dry them up. Ultimately two other property owners would be consulted regarding surface impacts on their property, and other water resources were identified and added to the monitoring schedule. There were two in stream monitoring points in the unnamed tributary to Beham Run that parallels Fleming Hollow Road; and 5 in stream monitoring points on Beham Run. In addition, 6 side hill springs in the mining area were being monitored (one the combined flow of several head of hollow springs), and one control spring was being monitored outside the study area. Two new springs emerged during the study period, and were monitored. The team also conducted visual observations of the road surfaces (dirt and gravel), culverts and abutments, fences, fields and wooded areas, and telephone poles to record any subsidence related impacts.

Water quantity monitoring points were identified with colored tape, and located with the use of GPS equipment, and placed on a GIS, which also includes the mine plan, and surface topographic features. Stream flows were measured with the use of a Marsh-McBirney flow meter. A Parshall flume was also used to measure some spring flows and stream flow in low flow conditions. Flow in some of the springs were measured using a container and stopwatch. A data base of the flow information was maintained and a printed copy of the information is included as an attachment. A map showing all monitoring points and progress of the mining is also included in the attachments.

A photographic record of the monthly monitoring visits was taken to help document the climatic and physical conditions throughout the period. Selected photographs are attached.

The use of GPS and GIS technology in this study became the topic of a technical paper presented at the American Society for Surface Mining and Reclamation 17^th Annual National Meeting, in Tampa, Florida, June 11-15, 2000.