论文部分内容阅读
Broken and jointed ground is extremely hazardous and requires unique stabilization techniques to pro-tect workers and critical entries. Bolting techniques, even the most advanced pre-load to create roof com-pression, can leave large gaps of unconfined and separated roof. This roof can also be susceptible to water inflows which only exacerbate the support problem. These types of conditions existed on long-term development main entry accessing several future longwall panels. The geotechnical assessment identified well defined jointing systems that also permitted water to flow between the roof separations, whichlu-bricated"the roof material and minimized any frictional advantages. Chemical injections of polyurethane materials, Minova Carbopur WS, was placed beyond the bolted horizon to move the water to the rib lines and reinforce the fractured and broken roof. The injection materials permitted the effective use of bolting patts and helped ensure long-term stability of critical entries. The paper describes the evaluation tech-niques, design patts, basis for chemical selection and application, and results and recommendations.