The progress of study on blasthole stemming and its action in borehole explosion is reviewed in the paper.

The author has analyzed comparatively the drawback of loess and water stemming and the main advantages of using chemical stemming,and also proposed chemical stemming suits for blasting coal mining,which has better economic,safety and social benefit.

Based on the production experience and the analysis on the aspects of iron notch depth,notch opening situation and slag tapping from the iron notch,the reasonable composition of gun mud is found out to improve its quality,and as a result,the iron tapping from the notch gets obvious improved.

The development and application of refractories used in iron runner,gun mud and hard extruding repairing material is introduced.

The research on tapping hole clay;

This paper presents the stem machine developed by Taoyuan Coal Mine and the new technology of the stemming material produdced with mechanization,and analyzes the safe results and economic benefits of the stemming material used in the coal mining.

This text introduces the domestic development state of the tapping hole clay,the corrosive mechanism about the tap hole,the raw material and its production craft flow,the development of the tapping hole clay and the technical progress of Baotou Steel Corp.

The process of recovery of refractories for ladle and the application of recovery material in blast furnace tap hole clay are introduced emphatically.

Practise of manufacture taphole clay for 2500m~3 BF in Bagang STEELS'

Non-water taphole clay was prepared by using 11% clay,3% SiO2,16% SiC,65% corundum,and 5% high-temperature asphalt powders as raw materials,adding more 16～18% tar as the binder and high alumina fly ash(0%,10%,15%,20%) additives respectively.