The objective of this investigation was to develop a program plan of analytical studies and tests to determine (1) the optimum installation tension of a coal mine roof bolt, (2) the most valid bolt support theory or theories, and (3) the most valid roof failure theory or theories. On this basis, a comprehensive literature search was made and significant material dealing with coal mine behavior, roof bolting, and roof support was collected, reviewed, classified, and analyzed. Emphasis was given to the influence of rock reinforcement on the control of deformation, stress field modification, and mine roof stability. An assessment was made of the effect of various parameters including bolt tension, bolt pattern, and time of installation on the effectiveness of rock reinforcement systems, and equations were developed for bolt tension as a function of these parameters and rock properties. From these studies, a major program plan of tests and studies was developed to verify and validate the most tenable theories of roof behavior and roof support and to determine optimum bolt installation tension.
We take your privacy seriously. You can review and change the way we collect information below.
These cookies allow us to count visits and traffic sources so we can measure and improve the performance of our site. They help us to know which pages are the most and least popular and see how visitors move around the site. All information these cookies collect is aggregated and therefore anonymous. If you do not allow these cookies we will not know when you have visited our site, and will not be able to monitor its performance.
Cookies used to make website functionality more relevant to you. These cookies perform functions like remembering presentation options or choices and, in some cases, delivery of web content that based on self-identified area of interests.
Cookies used to track the effectiveness of CDC public health campaigns through clickthrough data.
Cookies used to enable you to share pages and content that you find interesting on CDC.gov through third party social networking and other websites. These cookies may also be used for advertising purposes by these third parties.