In underground face blasting, the pull is found to be 10% less

Q. In underground face blasting, the pull is found to be 10% less than the drillhole length. The headings of 3.6 m width are supported by prop density of 1.44/m². The hole length is 1.5 m, and 6 rounds of blasting are done in the panel per shift. The number of props to be erected in a shift is                                                      .

Ans: 41.0-43.0