Stemming Ejection and Burden Movements of Small Borehole Blasts.
Paper in Second Internatl Symposium on Rock Fragmentation by Blasting Keystone Colorado Aug; :7 pages
The types and amounts of stemming material that are desirable in underground metal and nonmetal mine blasting to improve fragmentation while containing the hot gases are largely unknown. U.S. Bureau of Mines researchers examined the effectiveness of differing lengths of stemming by measuring stemming ejection times as related to burden movement. Test blasts at two surface limestone quarries were evaluated using high-speed photography. Cooling of explosive gases was calculated assuming adiabatic expansion as the gas worked its way into the fractured burden region. For the conditions of these tests, a stemming length of at least 26 charge diameters was found to prevent premature stemming ejection. In tests with stemming lengths of 16 charge diameters, the stemming was effective, but there was early venting of hot gases through fractures in the rock.
Paper in Second Internatl Symposium on Rock Fragmentation by Blasting, Keystone, Colorado Aug.23-26
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.