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
- Entry of Persons (Highwall mining) - waiting period is 7 days
- Barrier mining - waiting period is 3 months
(Barrier mining means extraction or drilling activities taking place within 20m of the external boundary, within 20m of an adjacent mine) - Emplacement areas - The waiting period is 3 months
- Electrical work on energised electrical equipment - waiting period is 7 days (but not if the electrical work is testing whether or not the equipment is energised)
- commissioning &/or recommissioning of a winding system - waiting period is 1 month
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
Fume Categories
6 levels Level 0. No fume, no gas 1 . Slight gas 2. Minor yellow/orange gas 3. Orange gas 4. Orange/red gas 5. Red/purple gas
Each category has 3 sub levels
a) Localised 1 to 5 holes
b) Medium less than 50% of shot
c) Extensive 50 – 100% of shot
Principal Hazard Management Plans
Ground and Strata
Roads and other vehicle operating areas
Airborne contaminants/dust
Spon Com
Subsidence
Inrush and Inundation
Fire and Explosion
Any other hazard identified under WHS Act Sec 34
Isolation
Four step process
Identify, Isolate, Lock, Test for dead
Associated Non-Technical Skills (ANTS)
Communication – Sharing ideas, getting feedback
Situational awareness – What’s happening around you
Decision Making – Choosing between various options
Leadership – Influencing others to understand what needs to be done
Teamwork - Working together to achieve a common goal
Stakeholders – The people involved
Elements of the Nertney Wheel
People, Plant, Procedures
Competent People
Safe work practices
Fit for purpose equipment
Controlled work Environment
Safe production
Reactive Ground
- The nitrates in the explosives react with the oxides in the rock – exothermic reaction
- Core samples sent away to lab
- Lab returns recommendations
- sleep time
- product selection
- use of urea (product inhibitor)
- load from initiation point
- divide mining areas into reactive and no reactive
10 Hurdles
Consultation
Hazard Identification/Hierarchy of Controls
Risk Assessment
Risk Management
Information to employees
Instruction & Training
Monitoring systems of work
Supervision
Review of operations
Revision and rectification
Spon Com
the oxidisation of carbonaceous material when exposed to air – exothermic reaction
