Question

Unit of payment in FPS of Explosive for blasting is __________

(a) kg

(b) per lb

(c) per gm

(d) per cu m

This question was posed to me in a job interview.

Enquiry is from Sizes and Dimensions of Various Works in MKS and FPS topic in division Nomography, Computer Aided Drafting & Procedure of Estimating of Civil Engineering Drawing

Answer 1

Correct answer is (b) per lb

Best explanation: Drilling and Blasting is the controlled use of explosives and other methods such as gas pressure blasting pyrotechnics, to break rock for excavation. It is practiced most often in mining, quarrying and civil engineering such as dam or road construction. The result of rock blasting is often known as a rock cut.

Drilling and Blasting currently utilizes many different varieties of explosives with different compositions and performance properties. Higher velocity explosives are used for relatively hard rock in order to shatter and break the rock, while low velocity explosives are used in soft rocks to generate more gas pressure and a greater heaving effect. For instance, an early 20th-century blasting manual compared the effects of black powder to that of a wedge, and dynamite to that of a hammer. The most commonly used explosives in mining today are ANFO based blends due to lower cost than dynamite.