Drilling Workshop Roy Rathner and Arne Lislerud
Optimisation of quarrying Pit-to-Product Mine-to-Mill Mine-to-Metal => requires a overview of operations, technology and markets
Overview of basic topics Organisation Mgt. Technology Pit Plant Sales Market analysis end-product volumes costs pricing stockpiling => right mix of all issues?
Key quarry performance indicators, KPI s key financial performance in a period overall quarry profitability capital employed (especially unscheduled stockpiling) key production performance in a period end-product tonnages, costs and margins productivity and cost per machine safety in operations public relations
How drilling and blasting affect downstream operations Drilling Blasting Loading Crushing sizing drill patterns drilling accuracy field performance of explosives shotrock fragmentation boulders floor humps fines and fragment microfractures muckpile profiles & swell loadability and loading capacities selectivity in mining & industrial mineral operations boulder downtime crushing capacities power consumption production of fines and waste
Rock drillability versus strength 300 Gabbro 300 200 200 Limestone Uniaxial Compressive Strength, UCS (MPa) 100 300 200 100 Coarse grained granite Mica gneiss Phyllite Greenstone Greenschist 20 30 40 50 60 70 80 90 100 Medium grained granite Mica schist Shale 100 300 200 100 Marble Calcerous Shale 20 30 40 50 60 70 80 90 100 Quartzite Sandstone Siltstone 20 30 40 50 60 70 80 90 100 Drilling Rate Index, DRI 20 30 40 50 60 70 80 90 100
Quality feed handling boulders boulder count dependent on primary crusher opening (and to a lesser extent primary crusher capacity) sort boulders from muck pile downsize boulders before entering primary crusher minimise boulder count using reduced uncharged height and/or tighter drill patterns
Quality feed effect of micro-fracturing Rock type Anorthosite Explosive Slurrit 50-10 Test blasts 4 x 50 000 tonnes Bench height 11 m Feed 0-950 mm Percentage of 0-32 (mm) 40 35 30 25 20 70 Ø76 Ø89 Ø102 80 90 100 110 120 Hole diameter, d (mm) Ø115 Large SUB from prior bench level Belt weights 32-64 mm 0-300 mm 0-70 mm 0-32 mm
Quarries and D&B contractors equipment flexibility and reliability D&B as to aggregate production requirements ability to handle difficult ground conditions availability of local / on-call field service
Criteria for selecting drills annual production requirements in bm3 or t critical diameter of explosives flexibility in usage application costing operator training and support operator comfort and safety ease of transport between pits D&B costs ( /t) 100 200 300 Drill-hole diameter (mm) => number of drills => hole size big enough? => different types of work => D&B costs per t Drill pattern, SB (m 2 ) 100 70 50 Better Better blastability 30 25 20 15 10 7 5 Finer fragmentation 50 70 100 150200 300400 Drill-hole diameter, d (mm)
Annual drill rig production capacities shifts per year 225 = 5 d/w 45 w/a shift hours per year 1800 = 8 h/d 5 d/w 45 w/a engine hours per year 1224 = 1800 68 % utilisation rock density, t/m 3 2.7 Annual production, Mtpa 2.8 2.4 2.0 1.6 1.2 0.8 0.4 Panteras - DP Rangers - DX CHA s - DC 51 2 64 2.5 76 3 89 3.5 102 4 115 4.5 127 5 Drill-hole size, mm
Occupational health and safety work related accidents for: mobile equipment hazardous work areas emissions control noise control dust control flyrock / charging / straight-hole drilling falling rocks / wall control => safety is linked as much to equipment as it is to attitudes => health, safety and environmental issues are everyone s concern => the ultimate safety target is zero harm not just a minimum occurrence of accidents
Assessment of some work related health risks Risk Musculoskeletal disorders Silicosis Oil mist Radon Vibrations 1950 1960 1970 1980 1990 2000 2010 Stress/mental workload Diesel Noise
Safety of inpit operations unwanted incidences do not just happen they have root causes actions can be taken so as to reduce frequency and consequences of unwanted occurrences the relationship between complexity and knowledge in the workforce is often unbalanced e.g. operator hazard training is a must! Premature ignition of electric detonators and blast due to lightning Pit wall failure burying 3 drill rigs in rubble
Safety of inpit operations new equipment requirements for the future? Rock fall source area Manditory 20m personnel exclusion zone from highwall? Rollover from terrain bench - 35m drop
Mina Alumbrera Double bench presplitting
Mina Alumbrera Pitwall scanlines
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