Practice of reducing tight bottom block of medium-length hole blasting

In this paper, the application and improvement of medium-length hole blasting in Piaotang mine area are introduced, the main problems of applying medium-length hole blasting in Piaotang mine area are pointed out and analysed, and some measures of improving blasting quality are put forward.

The paper analyse the mechanism of hole-bottom detonating and set forth the crushing mechanism of hole-bottom detonating in medium-length hole blasting decrease the production of big block ores.

The traditional method of hole-location in medium and deep hole blasting were according to engineer′s rough estimation for blasting region landform by eyenaked or with some simple measures, by this mean the parameters were made out and then adjusted in practice.

The basic theories of layered charging and layered tamping and the influences of explosive specific charge on distribution of explosive rock blocks for medium and deep hole blasting are discussed.

Apply "three small" technology and technology of middle-deep hole blasting to realize fast excavation in rock roadway;

After explosive properties and charging explosive structure are changed,for decreasing the big blasting block of medium-deep hole blasting the Houzhuang mine destrict of Jinling iron mine has taken some steps,for example to increase properly density factor value of blasting hole,etc The big block ratio is decreased from 25% to below 10

As a case study on slope improvement in a scrap mine,the design of medium-deep hole blasting parameter of network and safety proofreading are mainly presented,and the blasting results are analyzed.