West Virginia University West Virginia University investigated coal mine fields in Pittsburgh, using water level loggers, which can withstand highly corrosive conditions to continuously monitor the water level of the well for a multi-year period.
overview
Over the past 40 years, many coal mines underground throughout Appalachia -- primarily in West Virginia, Pennsylvania, and Maryland -- have closed for a variety of reasons. These include mining out of coal reserves, the closure of steel mills, and stricter environmental regulations such as the 1977 Mining Control and Recovery Act (SMCR).
A major coal seam in the northern West Virginia/Southwest Pennsylvania region the coal seam extends from Pittsburgh, Pennsylvania south to Clarksburg, west to the West Virginia region and Ohio. Coal in Pittsburgh once fired the blast furnaces of the coal industry and, more recently, generated electricity for much of the mid-Atlantic region.
While mining is still very active today, the number of active mines on this layer, which was once over 1,000, has dwindled to fewer than 10. Many mines have been closed and filled, or are in the process of being filled, with water.
Professionals from West Virginia University (WVU) have been investigating the Pittsburgh coalfield mines since 1998 to help answer a range of questions, including where is my water, how it is or may be treated, and where new discharges are likely to occur . The information is helping industry, national government and local remediation groups to better understand and plan for the impacts and risks of mine water discharges and to provide early warning of potential problems.
challenge
To pinpoint my pool and discharge, West Virginia University researchers needed a way to constantly monitor wells penetration water coal levels despite highly corrosive (acid, sulfate, and in some cases, methane-rich) water conditions and alternating hot and cold conditions. The team needed instrumentation that could not only withstand the harsh conditions, but also have enough battery power to last for years of deployment.
With funding from the U.S. Department of Energy (DOE), Department of Environmental Protection (WV wvdep), U.S. Environmental Protection Agency (EPA), and coal operations, the team was able to purchase a number of projects to vent water level loggers.
"Originally, we used ventilated data loggers, but they were really long and had trouble being deployed up to 800 feet below the surface," said Joe Donovan, director of the Hydrogeology Research Center at West Virginia University. "This length caused a lot of damage and we had to change the batteries every 2 months. Also, as the flooding progressed we had to take a large part of this bulky cable to the surface or store it in Wales. It's really A mess."
Donovan said the cold weather had problems with condensation on the LEDs on the loggers and sensors, despite trying various dehumidification combinations to reduce excess moisture. Failure of sensors, and in some cases loggers, due to moisture is a frequent occurrence.
solution
With these limitations, the West Virginia University team set out to identify alternative water-level data-logging instruments. They began to try to use HOBO® U20-001-01, U20-001-Ti, U20-001-02, U20-001-02Ti, U20-001-03, U20-001-03-Ti, U20-001-04, U20-001-04-Ti KIT-S-U20-04, KIT-D-U20-04, KIT-S-U20-01, KIT-D-U20-01, KIT-S-U20-02, KIT-D -U20-02, U20L-01, U20L-02, U20L-04 Water Level Logger ONSET, a Massachusetts manufacturer of portable data loggers and weather stations. Unlike previous loggers, which relied on bulky exhaust pipes and desiccant packs, the HOBO unit's airtight, airtight design makes logger deployment in basins quicker, easier, and more maintenance-free. The Logger also features a USB-based high-speed offload optical interface for data acquisition in wet environments. The optical design also eliminates the need for cumbersome mechanical connectors found in many traditional water level logging instruments. To prepare the 30+ loggers for deployment, first connect them to the research center computer via USB cable and configure a minute using the included Hoboware® Pro graph analysis software. Once configured, Logger is submerged in monitoring wells using a bulky 3/16" stainless steel cable attached to the hanging bolt. According to Donovan, readings are taken every hour and synchronized to a unified time base." Logger programs every Absolute pressure is recorded for an hour,” he explains. “Absolute pressure is recorded at good barometric pressure with the hoboware software, and then the sensor is flooded for pressure readings. The sensor flood is added to the sensor elevation to produce the head elevation of the mine water. "The loggers are offloading periodic data that can be analyzed. Depending on the particular good site, data retrievals may occur weekly, monthly, or every few months. It depends on who is consuming the data, while This in general, regulators report results more frequently.Retrieve data logger unloaded, loggers hold up sensor elevation in monitoring Wells with casing surface mounted spool.For more relevant parameters, you can contact Beijing They are then connected to a computer and the data is downloaded to hoboware for export to a custom data management system that Donovan and his team developed for data processing. Once the data is offloaded, the loggers are lowered back into the well Continue monitoring at the same elevation."The much lighter stainless steel cable is a fraction of the weight and cost of the old vent recording cable and is coated with vinyl for safety," he said. "Also, if we need to raise or lower the sensor height, we can cut the cable or connector on the new cable. Very simple job, comparing
result
Since deploying the HOBO U20-001-04 water level logger, Donovan, doctoral student Dave, and other researchers have been able to identify mining pools placed at the site of the complex coal-bearing basin while greatly simplifying monitoring operations. They no longer need to worry about replacing batteries every few months – logging operations for up to eight years on a single battery – because the logger U20-001-01
U20-001-02 U20-001-03 do not require vents, they are smaller and easier to deploy in surveillance wells. "The data we collected show that the Pittsburgh Coal Mine aquifer is late in the historical era of flooding and is expected to largely equilibrate to a new steady state by 2015," Donovan said. "At this time, flooding will be complete on the eastern and northern sides of the basin, and it is estimated that there will be 41 discharges of any appreciable size from flooded down-drain mines between Pittsburgh and East Chang, WV. Some of the discharge water remains Quite acidic, but many have become alkaline due to air repelling causing flooding. There is a wide range of water chemistry at play.” According to Donovan, the need for systems to track water levels in mines will continue. "Continued monitoring of these wells is necessary because pumping patterns can change and affect mine water distribution and pressure in coal mines," he said. "Additionally, some local pressurized sections of coal mines have the potential to discharge to the surface if not carefully controlled. Mine water is now also considered a potential source of water by the gas industry." "We monitor mine water levels in the area and we will continue as the story remains It's on."
