{"product_id":"2940013238374","title":"Toward Pillar Design To Prevent Collapse of Room-and-Pillar Mines","description":"In some instances, extensive room-and-pillar workings can collapse with little warning and pose a serious risk to underground miners. Traditional strength-based pillar design methods applicable to coal or hard-rock mines use a factor of safety defined as pillar strength divided by pillar stress. Factor of stability, defined as local mine stiffness divided by post-failure pillar stiffness, may offer a way to design room-and-pillar mines and eliminate collapses. Three alternative design approaches to decreasing the risk of large-scale catastrophic collapses are described: the containment approach, the prevention approach, and the full-extraction approach. Until good data on the post-failure behavior of pillars become available, the containment and full-extraction options are the safest. The limitations in our ability to evaluate both the stability of old workings and the long-term performance of room-and-pillar mines are described.","brand":"1001 Property Solutions LLC","offers":[{"title":"Default Title","offer_id":47082460774640,"sku":"2940013238374","price":1.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0737\/7593\/9824\/files\/2940013238374_p0.jpg?v=1763578380","url":"https:\/\/shop-qa.barnesandnoble.com\/products\/2940013238374","provider":"Barnes \u0026 Noble (DEV)","version":"1.0","type":"link"}