Technique and method of wall protection for drilling in the loose gravel stratum

Some accidents such as block-falling, collapsing and sticking happened in Quaternary loose gravel stratum during the construction of holes in the valley section of a sandstone uranium deposit of Xinjiang. They seriously affected the progress and quality of the project. To resolve the problems, drilling mud process and drilling method have been improved. After the improvement, the accident rate has dropped from 28% to 12%, and the success rate of accident treatment has risen from l-4.3% to 80%. Good results have been achieved. (authors)