Module 6 Overview

Module 6 Overview

We looked at unit operations in the last module, and learned that in a conventional cycle we have a drill-blast-load-haul sequence of operations; but we did not discuss the unit operation of blasting. We’ll do that in this module.

We use millions of pounds of explosives every week in mining to loosen overburden so that it is easier to dig, to break rock so that it can be freed from the rock face and loaded, and to create openings in underground mines, among dozens of other uses. Moreover, we do this with no injuries or fatalities and a minimum number of complaints from the mines’ neighbors. It is not an accident that we have achieved these positive outcomes; rather, it is good engineering.

In this module we’ll learn: about the blasting agents commonly used in the mining industry; how to design a blast round; how to initiate a blast; and how to avoid poor blasting outcomes.

Learning Outcomes

At the successful completion of this module, you should be able to:

• demonstrate knowledge of the basic properties of explosives, including oxygen balance, the basic concepts of fragmentation, the blasting agents, and the initiation technologies commonly used in mining;
• demonstrate knowledge of the design parameters for a blast:
  • burden, spacing, and free face,
  • hole diameter, length, stemming, decking,
  • powder factor,
  • fragmentation and throw,
  • ground vibration and air blast;
• demonstrate knowledge of typical blasting practices for:
  • bench blasting rounds for surface and underground mines,
  • stoping or drifting rounds;
• calculate:
  • powder factor for a given blast round,
  • burden, spacing, and stemming distance given a blast hole diameter or given a typical powder factor,
  • maximum charge weight/delay, given a vibration limit;
• demonstrate a knowledge of the factors that can adversely affect the outcome of a blast, or the relationship of poor engineering, drilling or explosives blending/loading practices on the outcome of the blast;
• identify potential safety and health issues, and proactive measures to prevent adverse outcomes, related to the following:
  • storage and handling,
  • flyrock,
  • fume and dust exposure,
  • air blast and vibration.