Sunday, 28 February 2021, 4:58 PM
Site: Blast Training International
Course: Blast Training International (BTI)
Glossary: Glossary
F

Formal Risk Assessment

A formal risk assessment will contain, as a minimum, the following components:

  • Step by step description of all the activities undertaken in the task
  • A list of the identified hazards or risks associated with each of the steps.
  • A description of the consequence of an adverse outcome.
  • An estimate of the liklihood or frequency, from never to always.
  • An estimated rating of the risk consequence, from insignificant to catastrophic.
  • An overall risk rating, Low, Moderate, High, Extreme, generally guided by a risk cube.
  • Existing and Addiitonal controls to manage the identified risks.
  • Signoff by the risk team

 

wrac

Example of completed Formal Risk Assessment.

risk cube

Example of Risk Cube to rate risk.

Fortan

The Fortan™ Advantage Bulk System heavy ANFO blends is specifically designed for difficult blasting applications found in open cut hard rock mining.

Fortan™ Advantage is designed to increase explosive energy in dry blastholes, however the higher density emulsion blend of Fortan™ Advantage 50 can be used in dewatered blast holes.

The AN content enables high heave to be achieved. It is not suitable for ground containing reactive sulphide.

Fragmentation

The size distribution of material left in the muck pile after the blast.
An increase in fragmentation corresponds to a higher percentage of rock fragments passing through a particular aperture size.

Free End

A face or void aligned at the end of the rows of the blast.
The free end provides holes on the end of the rows with relief in two directions, to the face and to the end.

Friction Sensitivity

Friction sensitivity testing can be completed using the BAM Friction apparatus developed by the German Federal Institute for Testing and Materials (BAM). The test is used to measure the sensitivity of test materials to frictional stimuli. The test is a part of UN Test Series 3 which is sued to assess the ignition sensitivity of suspected explosive materials. A 10mm3 sample is spread on a porcelain plate and the plate is then dragged under a weighted porcelain peg. The force on the peg is varied and the limiting friction load is determined as the lowest force for which a flash, flame, or explosion is observed. As many as 60 trials may be performed, and therefore approximately 1 cubic centimeter (cc) of sample may be required.

Fume

Fume is the general term for toxic gases produced by blasting.

fume class 4

NOx Fume produced from a surface blast.

The common fumes are carbon monoxide (CO) and oxides of nitrogen (NOx)

The group of gases known as Oxides of Nitrogen or NOx, of which the most common are nitric oxide (NO) and nitrogen dioxide (NO2), are often found as by-products in the post-blast gases of ammonium nitrate-based explosives. Together, these gases are loosely referred to as "NOx". Nitric oxide is invisible, but nitrogen dioxide ranges from yellow to dark red depending on the concentration and size of the gas cloud. These gases are toxic.

There are a number of causes for fume generation. These include:

  • Explosives delivered into the blasthole with poor Oxygen Balance
  • Lack of confinement in soft ground
  • Loading into wet ground
  • Dynamic desensitisation

The attached file provides detailed information on fume generation and management.

 

Fuse Head

The combination of bridge wire and pyrotechnic substances which when subjected to electric current provides ignition to the detonator.

Fuse heads

G

Gas Bag

An inflatable bladder used to block off a blast hole and support explosives or stemming.

gas bag

Geophone

A geophone is a device that converts ground movement (velocity) into voltage.

Geophones typically comprise a spring-mounted magnetic mass moving within a wire coil to generate an electrical signal. The response of a coil/magnet geophone is proportional to ground velocity.

Geophones for recording blasting vibration should be able to record from 0.1mm/sec to 300mm/sec and over a frequency range from 4.5 Hz to 250 Hz.

geophone

Geophones require annual calibration by an approved testing station (NATA) to ensure they continue to accurately record ground vibration.

Geotechnical failure modes

There are a number of common failure modes relating to rock slope stability.

These are: