bpg_a3water management for hydrometallurgical process plants (1)

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)

THANK YOU