OCE Tutorial Notes Flashcards
Misfire
a charge or part of a charge that has failed to initiate or go off
Vibration
Maximum 10mm/s 95% must be below 5mm/s measured over 12-month period
Burn Front
the distance the initiation system has functioned in front of the blast generally, 5-6 holes achieved by down hole delay 600m/s @HVO used to prevent cutoffs only used in NONEL
Methane CH4
Density 0.55 naturally rises
Explosive range 5-15%
Detector set at 5% of LEL approx. 0.25%
High Risk Activities
High wall mining waiting period is 1 month Barrier mining Barrier mining means extraction or drilling activities taking place within 20m of the external boundary, within 20m of an adjacent mine Waiting period is 3 months Emplacement areas The waiting period is 3 months
Overpressure
Maximum noise from a blast max 120db 95% must be below 115db measured over 12-month period
Order 34
Training and Competence Training of new employees Training of existing employees in a new skill Training of contractors Reassessments Audits
Order 42
Respirable Dust
Gives power to inspectors to enter mines to carry out monitoring of airborne dust, collect dust samples and other activities relating to the collection of airborne dust samples
Frequency of sampling for respirable dust, respirable quartz, and inhalable dust – not to exceed 12 months
Samples to be collected from breathing zones of at least 5 people including, Drillers, Shotfirers, Stemmers and mobile equipment operators
Carbon Monoxide CO
Density 0.97
Highly poisonous
Detector set at 30ppm
Oxygen O2
20.93% in normal air
Density 1.11
Detector alarms when drops below 19%
Wont support combustion below 17%
Hierarchy of Controls
Where Elimination is not possible you are required to use Substition, Isolation, Engineering, Administration, PPE, or a combination of,to reduce the risk to as low as reasonably practical.
Maximum Instantaneous Charge (MIC)
the maximum amount of explosive that can be set off at one time
3000kg at HVO
Fume
Incomplete combustion of the explosive product, gives off NOx gas Poor shot design Poor on bench practice Water in holes Strata Geology Type/quality of explosives
Order 43
Health Monitoring
Requirement for pre placement medicals
Requirement for pre placement chest x-ray
Requirement for period medicals – every 3 years
Requirement for periodic chest x-ray
Requirement for exit medicals
Requirement for operator to supply list of coal mine workers, must be supplied by 31st of October every year
Plan, Do, Check, Act
Plan – Define and analyse the problem
Do – Devise a solution, develop a detailed action plan
Check – Check outcomes against the plan, identify deviations and issues
Act – Standardise solutions, review and devise next actions
Hydrogen Sulphide H2S
Density 1.18 heavier than air
Smells like rotten eggs
Explosive range 4.5-45%
Maximum allowable concentration (MAC) 10ppm
