A series of test foundations damaged during a longwall mining operation were left with permanent tilt, curvature, and substantial cracking. Two of the foundations were releveled using continuous lift piers. The continuous lift piers removed the tilt and curvature and significantly reduced the width of the foundation cracks. Following the releveling of the foundations, an adjacent longwall panel was mined, resulting in additional subsidence, although of smaller magnitude. The response of the releveled foundations was monitored and compared with the response of a footing that was not releveled. Although the continuous pier system does not strengthen the structure and distortion was observed during the second event, the system permitted the deformations to be removed in a few hours. Introduction Ground subsidence due to underground mining activities is a significant problem affecting mine operators, the insurance industry, government agencies, and property owners. In the United States, damage to residential structures from underground mining is estimated between $25 and $35 million each year (Gray 1988). With approximately 5 .2 million acres of abandoned or inactive coal mines, of which 500,000 acres are in populated urban areas (Dyni and Burnett 1993), damage repair techniques applicable to residential and light commercial structures must be developed. Effective damage remediation methods can only be developed with a good understanding of the mechanisms causing structural distress. Since structures in subsidence prone areas are often subjected to multiple or recurring ground deformation events, the response of repaired structures during subsequent subsidence events must also be evaluated. Damage to structures from subsidence occurs primarily over inactive or abandoned room-and-pillar mine operations and may occur many years after the coal has been extracted. Since modem longwall techniques result in subsidence that is immediate and can be predicted with some degree of certainty, structural damage can often be reduced or eliminated by premining measures. Although damage due to longwall mining is not as significant an economic issue as damage from abandoned mine operations, the controlled nature of longwall induced subsidence provides a good opportunity to observe the mechanisms governing structural damage. The response of structures to mining induced subsidence is complex. Structural behavior and damage are dependent upon the relative properties of the foundation and underlying soil, and depend significantly on the magnitude of the ground movements. This coupling of soil and structural response is known as Soil-StructureInteraction (SSI). Monitoring full-or reduced-scale structures during subsidence has provided useful observations 'Paper presented at the International Land Reclamation and Mine Drainage Conference and Third International Conference on the Abatement of Acid Drainage, Pittsburgh, PA, April 24-29, 1994. 2Eric C. Drumm and Richard M. Bennett, Associate Professor, Department of Civil and Environmental Engineering, The University of Tennessee, Knoxville 3Guoming Lin, Engineer, S&ME, Savannah, GA 'David B. Raaf, President, Atlas Systems, Inc., Independence, MO 'Dean Daugherty, Atlas Foundation Repair Systems, St. Louis, MO