Glossary


glossary

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H

Half Spaced

Where additional blastholes are drilled between those on the designed pattern to increase energy along the row.

Entry link: Half Spaced

Hazard Classification

A statement of the class, division and compatibility group to which an explosive has been assigned in accordance with the Australian Code for the Transport of Explosives by Road and Rail (known as the AE Code).

The main hazard classifications for explosives are:

1.1 Mass explosion hazard. If any part of the inventory detonates the bulk of the inventory will sympathetically detonate.

1.4 No risk of a mass explosion. Should part of the inventory detonate there is no risk of the remainder sympathetically detonating.

Entry link: Hazard Classification

Heavy ANFO

Heavy ANFO is a blend of ANFO with up to 50% emulsion added.

Adding emulsion replaces some of the air pockets between the prills and increases the density, energy and water resistance whilst reducing sensitivity.

Heavy ANFO is sensitised by the remaining air gaps between and within the AN prills and does not generally require chemical gassing.

Heavy ANFO is generally to thick to pump and must be augered into blastholes.

Entry link: Heavy ANFO

Hectare

An area of land measuring 100m by 100m.

Total area of 10,000 square meters. Equivalenet to about 2.5 acres

Entry link: Hectare

Hertz

Hertz (abbreviated: Hz) is the standard unit of measurement used for measuring frequency. Since frequency is measured in cycles per second, one hertz equals one cycle per second.

Hertz is used commonly used to measure wave frequencies, such as sound waves, light waves, and radio waves. For example, the average human ear can detect sound waves between 20 and 20,000 Hz. Sound waves close to 20 Hz have a low pitch and are called "bass" frequencies. Sound waves above 5,000 Hz have a high pitch and are called "treble" frequencies

low and high freq

Human hearing can pick up sounds at frequencies between 20 Hz and 20,000 Hz

Ground vibration from blasting occurs over a wide range of frequencies.

Entry link: Hertz

Hierarchy of Control

Hierarchy of hazard control is a system used in industry to minimize or eliminate exposure to hazards. It is a widely accepted system promoted by numerous safety organizations. This concept is taught to managers in industry, to be promoted as standard practice in the workplace. Various illustrations are used to depict this system, most commonly a triangle.

 

The hierarchy of hazard controls are, in order of decreasing effectiveness:

 hierarch of control

Elimination

Eliminating the hazard—physically removing it—is the most effective hazard control. For example, if employees must work high above the ground, the hazard can be eliminated by moving the piece they are working on to ground level to eliminate the need to work at heights.

 

Substitution

Substitution, the second most effective hazard control, involves replacing something that produces a hazard (similar to elimination) with something that does not produce a hazard—for example, replacing lead based paint with acrylic paint. To be an effective control, the new product must not produce another hazard. Because airborne dust can be hazardous, if a product can be purchased with a larger particle size, the smaller product may effectively be substituted with the larger product.

 

Engineered controls

The third most effective means of controlling hazards is engineered controls. These do not eliminate hazards, but rather isolate people from hazards. Capital costs of engineered controls tend to be higher than less effective controls in the hierarchy, however they may reduce future costs. For example, a crew might build a work platform rather than purchase, replace, and maintain fall arrest equipment. "Enclosure and isolation" creates a physical barrier between personnel and hazards, such as using remotely controlled equipment. Fume hoods can remove airborne contaminants as a means of engineered control.

 

Administrative controls

Administrative controls are changes to the way people work. Examples of administrative controls include procedure changes, employee training, and installation of signs and warning labels (such as those in the Workplace Hazardous Materials Information System). Administrative controls do not remove hazards, but limit or prevent people's exposure to the hazards, such as completing road construction at night when fewer people are driving.

 

Personal protective equipment

Personal protective equipment (PPE) includes gloves, respirators, hard hats, safety glasses, high-visibility clothing, and safety footwear. PPE is the least effective means of controlling hazards because of the high potential for damage to render PPE ineffective. Additionally, some PPE, such as respirators, increase physiological effort to complete a task and, therefore, may require medical examinations to ensure workers can use the PPE without risking their health.

Entry link: Hierarchy of Control

High Temperature Blasting

Blasting which is carried out in material at a temperature of 100°C or greater.

Entry link: High Temperature Blasting

Hit Mark

Point of impact on receptor from donor, typically related to shock tube.

hitmark

Hit mark from properly functioning low energy surface delay on shock tube.

Entry link: Hit Mark

HMX

Cyclotetramethylene tetranitramine, a high explosive used in the core loading of shock / signal tube and in high temperature applications.

HMX, also called octogen, is a powerful and relatively insensitive nitroamine high explosive, chemically related to RDX

The molecular structure of HMX consists of an eight-membered ring of alternating carbon and nitrogen atoms, with a nitro group attached to each nitrogen atom. Because of its high molecular weight, it is one of the most potent chemical explosives manufactured

HMX Structure

Entry link: HMX

HNS

Hexanitrostilbene (HNS), also called JD-X, is a heat resistant high explosive developed at the Naval Ordnance Laboratory in the 1960s.

HNS boasts a higher insensitivity to heat than TNT, and like TNT it is very insensitive to impact.

Entry link: HNS


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