bpg_a3water management for hydrometallurgical process plants (1)
DESCRIPTION
Mine pollution managementTRANSCRIPT
BEST PRACTICE GUIDELINES FOR WATER RESOURCE PROTECTION IN THE SOUTH AFRICAN
MINING INDUSTRY
BPG A3 :
WATER MANAGEMENTIN
HYDROMETALLURGICAL PROCESSING PLANTS
HYDROMETALLURGICALMINERALS PROCESSING
PLANT
U/GROUNDMINING
OPERATION
MINE RESIDUEDISPOSALFACILITY
WET ORE
MINE WATER
SOLID WASTE
PROCESS WATER
RETURN WATERSURFACEMINING
OPERATION PROD
UCT
BPG A6
BPG A5
BPG A2BPG A3
EMIS
SION
S
HYDROMETALLURGICALMINERALS PROCESSING
PLANT
HYDROMETALLURGICALMINERALS PROCESSING
PLANT
U/GROUNDMINING
OPERATION
MINE RESIDUEDISPOSALFACILITY
MINE RESIDUEDISPOSALFACILITY
WET ORE
MINE WATER
SOLID WASTE
PROCESS WATER
RETURN WATERSURFACEMINING
OPERATION PROD
UCT
BPG A6
BPG A5
BPG A2BPG A3
EMIS
SION
S
Hydrometallurgical processing plants
Milling & grinding circuitsSeparation circuitsRefining circuits
Classifiers, hydrocyclones, screens, filters, thickeners, flotation processes, leaching, electro-winning, solvent extraction, metal recovery, precipitation
Importance of BPG
Significant user of waterProducer of water containing wasteWater conservation (scarce, valuable)Sustainable water use (user demand)Waste discharge charge system
(economics)
Water management objectives
Water reuse to reduce discharge
Avoid / reduce effects on plant efficiency
Avoid / reduce impact on environment (universal solvent)
Applicability of BPG
Aimed at water containing waste in hydrometallurgical processing plants on all types of mines
Simplified: Small-scale miningExcluded: Pyrometallurgical & smelter
operations
Objectives of BPG
Promote strategic water management approach– Water as key business asset– Water has social, cultural, environmental &
economic valueProvide practical & logical process to
optimise water management
ConsiderationsUnderstand true cost & value of waterApply good housekeeping & operating practicesPollution prevention & reduction at sourceOptimise water management systemsInspection, monitoring, auditing, maintenanceReview resource intakeOptimise water reuse & reclamationInvestigate cleaner technologies or modificationsWater & waste management programme
Legal frameworkDWAF– Custodian of water resources– Responsibility: protection of water resources– Focus: environmental impact
Acts – ECA, NEMA, MPRDANWA (Act 36 of 1998)GN 704 Minimum Requirements – waste managementIWWM (legal: EMP & WULA)
Mine life cycle – exploration, prospecting, planning, design
Decisions at this stage : 85% of costLife-cycle assessment (cradle-to-grave)EIA (acceptable levels)Risk assessment & managementEfficiency & optimisationFeasibility studiesTechnologies (consider & evaluate)Inputs (water, energy, raw material)Outputs (minimise waste mass)
Mine life cycle – commissioning & operationalImplementationHealth & safety measuresPollution prevention strategiesGood housekeeping & operating practicesTechnologies (evaluate & modify/improve)EMS (effective control)Improve water managementMonitoring (BPG G3)Water & salt balance (BPG G2)
Mine life cycle – decommissioning, closure & post-closure
Residual impacts – monitoring, performance assessment, predictive modeling
Water management – BPEOFinances & contracts – infrastructure
maintenance, land owner
Financial considerations
1. Water as key business assetShared community resourceScarce & valuable commodity (conserve)DWAF – manage & allocateRecycling VS potable use (benefit)Pro-active: prevent VS mitigateReuse & reclamation (BPG H3)Water management (public view, external
review)
2. True cost of waterExploration, prospecting & planningWater supply (boreholes, service provider)Social, cultural, environmental & ecologicalEconomic feasibility (expenses & income)Waste management & dischargeOperational (infrastructure & equipment)Water reticulation & effluent treatmentMaintenance & remediationLabour (skills & training)Legal & risk
2. Value of water
Cultural, social & spiritual Value of ecosystemCompeting demandsImpacts on downstream usersCost to operationEconomic production valueLoss of income, jobs or market share
Information gathering
3. Site & process knowledgeManage what you know
Site – layout, locality etcEnvironment – climate, geohydrology etcProcess – flow diagram, infrastructure etcInputs – characteristics, geochemistryResources – water, finance, staffMine/plant water users – quantity & qualityWaste – handling, hazardousnessWater reticulation – separate circuits etcMonitoring – impacts & pollution plume
4. Water & salt balancesBPG G2 – water management tool
Objectives: current & futureDivisions: smaller management unitsUpdates: expansions or changesLoads: conservative saltsCalculation of unknownsHydrological cycle: seasonsOutput: level of detail, accuracy
5. Mine / plant water users
Water quantity requirementsWater quality requirementsSensitivity to variability / changesContaminants of concernPollution loadsWater reuse & reclamation (BPG H3)Water treatment (BPG H4)
6. Housekeeping & water management practices
Uses: dust control, transport, cooling/heating Water segregation – level of contaminationMaterial storage – plan position, water contactHigh contamination risk areas – bundStorm water management – clean & dirtyCleaning – clean spills immediately, use of waterEquipment & maintenance (pro-active)Sustainability – mine phase, plant life cycle
7. Constituents of concernMinimise generation of contaminants– Significant quantity, available for uptake & potential to
cause harm/impact– Review inputs (quantity, locality, alternatives)– Optimise pollution prevention & reduction at sources
(Step 6)Plant/mine water user quality requirements– Process performance– Product quality / yieldMonitoring (BPG G3), maintenance &
inspections / audits
8. Water reuse & reclamation (BPG H3)
Reason: scarcity, demand, reduce dischargesOpportunities: large quantities used & dischargedBenefits: save cost, water conservation, limit
liabilitiesConsiderationsWater sources Minimise intake & lossesWater use inventory Reticulation (link)Discharges/disposal Treatment (BPG H4)Alternative uses MonitoringBy-product recovery SustainabilityFuture projections/predictions
9. Process changes & cleaner technology
Pro-active & preventative approachAim: ecological & economical efficiencyReduce: pollutant levels, waste, water
requirements, impactImplementation:
– Identify– Assess applicability & practicality– Feasibility– Monitor
9. Cleaner technologyBarriers / constraints:
– Economical (lack of resources, commodity price)
– Technological (structural, info gaps)– Legislative (changing, lack enforcement)Overcoming barriers:
– Government intervention (incentives, assist)– Education & training (knowledge, awareness)– Improved planning (new vs existing)
10 & 11. IWWMP
Continuous systematic improvement (pollution prevention, impact minimisation)
Required for implementation– Resources (staff, finances)– Commitment (objectives/goals, staff)– Monitoring (BPG G3)– Training & awareness– Action plans
10 & 11. IWWMP ContentGeneral – layout, processLegislation – existing, requiredWater environment – climate, catchmentProcess water management (sources; users; BPG H3)Storm water management (clean & dirty)Groundwater management (pollution plume; impact)Water treatment (BPG H4)Disposal/discharge (options/alternatives, impact)Waste management (classification, leaching)Commitments (monitoring, management)Consultation process (users, authorities)
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