Subsidence Mitigation

Our staff has performed several million dollars’ worth of subsidence mitigation projects.  These services generally pertain to the mitigation of subsurface voids left behind from historical underground mine workings.  To complete these projects, Western conducts extensive research to determine what information about the mine workings exists.  Risks are evaluated to determine if any buildings, infrastructure, or people are at risk of being damaged or hurt.  Once this information is obtained and compiled, it used in conjunction with modern survey information to create the project area and design the borehole pattern that will best fill the existing voids.  Once the pattern has been created, exploratory drilling is performed to confirm the accuracy of design mapping.  Once the mapping has been adjusted or confirmed, production drilling and injection grouting commences. Western’s role at this point in the project is inspection of drilling and grouting operations to ensure that they meet project plans and specifications, and testing of the grout before pumping to confirm that it meets the properties set forth during design.  Western also performs construction management on behalf of the client throughout the project.  Construction management generally consists of preparing bid documents, conducting bid tours, prequalifying potential bidders, reviewing bids from qualified contractors, drilling inspection, e-log interpretation, grout inspection, and reviewing and approving the contractor’s pay applications.  Interpretations of e-logs are performed to determine where grout needs to be placed.  Having read thousands of e-logs, Western can quickly interpret these logs to assist the contractor in his/her grouting operations.  Inspection during the project allows Western to make adjustments and recommendations to the contractor in order to assure that the area has been effectively mitigated.  Western can perform many other functions during the project such as documentation, as-builts, and special exploratory techniques such as down-hole video.