Rock masses are initially stressed in their current in situ state of stress and to a lesser natural state. Whether one is interested in the extent on the monitoring of stress change. formation of geological structures (folds, faults, The subject of paleostresses is only briefly intrusions, etc. ), the stability of artificial struc discussed. tures (tunnels, caverns, mines, surface excava The last 30 years have seen a major advance our knowledge and understanding of rock tions, etc. ), or the stability of boreholes, a in the in situ or virgin stress field, stress. A large body of data is now available on knowledge of along with other rock mass properties, is the state of stress in the near surface of the needed in order to predict the response of rock Earth's crust (upper 3-4km of the crust). masses to the disturbance associated with those Various theories have been proposed regarding structures. Stress in rock is usually described the origin of in situ stresses and how gravity, within the context of continuum mechanics. It is tectonics, erosion, lateral straining, rock fabric, defined at a point and is represented by a glaciation and deglaciation, topography, curva second-order Cartesian tensor with six compo ture of the Earth and other active geological nents. Because of its definition, rock stress is an features and processes contribute to the current enigmatic and fictitious quantity creating chal in situ stress field.

The best of ground control technology, 40 years in the making. Developments in Ground Control summarizes the objectives, methodology used, and major conclusions reached from papers presented and published in the International Conference on Ground Control in Mining (ICGCM) proceedings from 1981 to 2020. Because the subject areas of the papers published in the proceedings are so broad, ranging from accident training and coal/rock bursts to geology, pillar, multiseam mining, in situ stresses, roof falls, and roof supports to surface subsidence, the papers were grouped into 13 aggregate topics and addressed separately in 13 book chapters by 13 authors from 4 countries. These book chapters are a fresh look at the topics, providing new insights, sourcing older papers, and summarizing data. This is an enormous help for those seeking information on ground control. There were 1,795 papers in the 40 years of ICGCM proceedings in more than 40 ground control topical areas. It would certainly be very time consuming if not impossible to find the right papers of interest in a timely manner. This book makes it easy for interested people to find the progress, application, and achievements of certain techniques from the past 40 years and how they affected the field of ground control and the world mining industry, in particular, the United States. Generally speaking, most researchers tend to favor recent developments when performing a literature search, ignoring or considering old papers outdated. In contrast, over the last 40 years, most research findings for a specific topic in ICGCM received continuing attention for subsequent development or repeated citations if applications were successful.