Mine Subsdence Mitigations
The Hughes Corporation has performed subsidence mitigations on hundreds of structures of all shapes and sizes. All of our subsidence mitigations have been successful in minimizing the damages caused by longwall mining. We have yet to encounter any damage that could not be repaired. We have completed and consulted on projects spanning from the Eastern to the Mid-Western United States.
To begin the subsidence mitigation process the recommended mitigation measures are constructed using the methods that are detailed above. Upon receiving the recommended subsidence mitigation measures we meet with the property owners to discuss the mitigation in full detail addressing any questions or concerns. Our main focus is to walk the property owner through the mitigation step by step from the beginning of the process until the repairs are completed. We serve as the property owner’s main contact throughout the mitigation. It is at this time that we review and mark all utility lines that are on the property that may be in the way of any recommended trenching. Information is gathered from appliances, and if necessary a conversion from natural gas to an alternate heating source during the mining period is orchestrated. The next step is to implement the recommended mitigation measures which usually involve trenching, wrapping the structures with steel cables to the recommended tensions, adding bracing to weak areas of the structure, and adding additional structural support. We are careful to keep the property owner informed and aware of our next steps as the process moves along. From this point until the mining period has ended we check in on the property anywhere from one to three times per day depending on the location of the longwall. We have kept crews on site for twenty four hour periods to monitor the properties when it is requested. During our inspections of the properties we adjust the cable tensions as needed to ensure that the tensions stay as constant as possible. The heaviest period of monitoring the properties occurs when the longwall is within 400’ of a structure until they are about 400' beyond a structure. Once the longwall is 1,000 feet beyond a structure we will begin to remove our mitigation methods that were implemented. At this point in the process we analyze the damage and prepare an estimate to repair the damage. Repairs are scheduled and coordinated with the property owner. The structures and property are now returned to their pre-mining state. The most common repairs after subsidence are minor repairs to foundation mortar joints, repairs to cracking in drywall or plaster, adjustments to windows and doors, and repairs to slips or cracks in the surrounding land.