What are two types of blast hole layout patterns?

• A. Single row and cross row
• B. Single row and multiple row
• C. Circular and straight
• D. Multiple row and square

Answer: (B)

The explanation for identifying single row and multiple row as types of blast hole layout patterns lies in understanding the fundamental designs used in blasting operations.

A single row pattern involves placing blast holes in a single line, which is often used for quarrying or in situations where a clean break is required. This layout makes it easier to control the fragmentation of the rock and can be more efficient in certain types of blasting scenarios.

In contrast, a multiple row pattern consists of several rows of blast holes that can be staggered or aligned in a systematic layout. This approach is utilized to achieve more significant rock displacement and is essential when larger volumes of rock need to be blasted simultaneously. The multiple row pattern allows for improved uniformity in rock fragmentation, which can lead to more efficient material handling post-blast.

These two types reflect the strategic decisions made in blaster designs to optimize the outcomes of blasting operations based on rock characteristics, project requirements, and safety considerations. Other patterns, while valid in certain contexts, do not encompass the foundational methods used as does the combination of single and multiple row configurations.