Coal mines are continuously seeking to determine the performance of entries with different ground control products and installation methods. There are many factors that impact how an entry will perform which include but are not limited to geology, overburden, bolting type and pattern, and mine design. At the National Institute for Occupational Safety and Health (NIOSH), research has been instituted to examine the relationship of the parts of a coal mine entry as a system and not as individual components. To study this relationship, the first step in this study was to create a numeric rating system that accurately reflects visual observations of the mine entry and is easy to implement. NIOSH researchers devised this rating system to improve upon previous ideas, offering increased flexibility which can be incorporated into an overall entry condition that offers different levels of confidence based on the user’s time devoted to the inspection. This new entry rating system was implemented at three different mines over varying periods of time to evaluate the ground response to the geology, bolt installation pattern, stress changes by mining, overburden, and time dependency.

煤矿不断寻求确定具有不同地面控制产品和安装方法的入口的性能。有许多因素会影响一个入口的性能，包括但不限于地质、覆盖层、锚杆类型和模式以及矿山设计。美国国家职业安全与健康研究所 (NIOSH) 开展了一项研究，将煤矿入口的各个部分的关系作为一个系统而不是作为单个组件进行检查。为了研究这种关系，本研究的第一步是创建一个数字评级系统，该系统准确反映了对矿山入口的视觉观察，并且易于实施。NIOSH 研究人员设计了这个评级系统来改进以前的想法，提供更大的灵活性，可以结合到整体进入条件中，根据用户用于检查的时间提供不同程度的信心。这个新的进入评级系统在三个不同的矿山在不同的时间段内实施，以评估地面对地质、螺栓安装模式、采矿应力变化、覆盖层和时间依赖性的响应。