Resolution Copper Mine Water Treatment Plant - OverviewPlant Performance – Water Quality Water...
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Resolution Copper Mine Water Treatment Plant - Overview INAP Water Treatment Workshop October 7, 2009
Transcript of Resolution Copper Mine Water Treatment Plant - OverviewPlant Performance – Water Quality Water...
Resolution CopperMine Water Treatment Plant - Overview
INAPWater Treatment Workshop
October 7, 2009
2 22 June 2009 Confidential; © Copyright Protected
Forward-Looking StatementsThis presentation includes “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. All statements other than statements of historical facts included in this presentation, including, without limitation, those regarding Rio Tinto’s financial position, business strategy, plans and objectives of management for future operations (including development plans and objectives relating to Rio Tinto’s products, production forecasts and reserve and resource positions), are forward-looking statements. Such forward-looking statements involve known and unknown risks, uncertainties and other factors which may cause the actual results, performance or achievements of Rio Tinto, or industry results, to be materially different from any future results, performance or achievements expressed or implied by such forward-looking statements. Such forward-looking statements are based on numerous assumptions regarding Rio Tinto’s present and future business strategies and the environment in which Rio Tinto will operate in the future. Among the important factors that could cause Rio Tinto’s actual results, performance or achievements to differ materially from those in the forward-looking statements include, among others, levels of actual production during any period, levels of demand and market prices, the ability to produce and transport products profitably, the impact of foreign currency exchange rates on market prices and operating costs, operational problems, political uncertainty and economic conditions in relevant areas of the world, the actions of competitors, activities by governmental authorities such as changes in taxation or regulation and such other risk factors identified in Rio Tinto's most recent Annual Report on Form 20-F filed with the United States Securities and Exchange Commission (the "SEC") or Form 6-Ks furnished to the SEC. Forward-looking statements should, therefore, be construed in light of such risk factors and undue reliance should not be placed on forward-looking statements. These forward-looking statements speak only as of the date of this presentation. Rio Tinto expressly disclaims any obligation or undertaking (except as required by applicable law, the UK Listing Rules, the Disclosure and Transparency Rules of the Financial Services Authority and the Listing Rules of the Australian Securities Exchange) to release publicly any updates or revisions to any forward-looking statement contained herein to reflect any change in Rio Tinto’s expectations with regard thereto or any change in events, conditions or circumstances on which any such statement is based.
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Resolution Copper Mining
• Resolution Copper Mining (RCM) is a limited liability company • Ownership:
– Resolution Copper Company (55%), a Rio Tinto plc subsidiary– BHP Copper, Inc. (45%), a BHP-Billiton plc subsidiary
• Large, underground Cu/Mo deposit in Magma Mine district
• Present status– Undertaking pre-feasibility studies– Sinking Shaft 10 for characterization– Pursuing land exchange
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Regional map
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Project area aerial view
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Background – Resolution Copper De-watering Project
• De-watering the Magma Mine ahead of shaft sinking– Approximately 2-billion gallons stored
• Two pumps placed in #9 shaft, 4770’ feet deep– Pipeline out the Never Sweat tunnel – New water treatment plant built on old Magma mill site
• Water delivered to New Magma Irrigation Drainage District (NMIDD)– Water co-mingled with CAP water
• Solid sludge stored on-site, adjacent to WTP in lined ponds
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27-mile 18” HDPE pipeline, gravity flow
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NMIDD Demand
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Mine Water Chemistry
• Moderately depressed pH (5.7 – 5.9) from carbonic acid
• Elevated temperature: 110 – 115oF• High dissolved solids: 5,000 – 5,500 g/l;
predominately sulfate• Very little variation in mine water
chemistry to date
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Plant Process – High Density Sludge
• Add lime to precipitate metals• Recycle the solid sludge to enhance plant efficiency and reduce
sludge storage volume
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Process Targets
• Effectively remove dissolved metals• Generate a high solids density sludge• Produce water low in TSS• Add soda ash to reduce the Ca2+ level• Keep the Sodium Adsorption Ratio (SAR) low
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Process Targets - Effectively remove dissolved metals
• Add lime to raise the pH• Plant initially operated at pH = 9.3 in Reactor B
– Lowered to 9.0 very soon after good effluent assays– Lowered again to 8.7 after lab tests and a short plant trial returned similar
dissolved metals to pH = 9.0– Potential to lower pH again
• CaO consumption is currently 6.7 lbs/1,000 gal– Consumption down 25-30% with pH drop to 8.7
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Process Targets - Generate a high solids density sludge
• Sludge generation– Sludge generation currently 10 lbs/1,000 gallons – Or 18 tpd at 2,500 gpm influent
• Recycle sludge to generate large layered particles - like an onion– Better settling rates, higher sludge densities– Recycle rate is about 24:1– Sending sludge to SSI pond, or “wasting”, typically at 25-30% solids
• Wasting at high solids and low flows allows for excellent evaporation and final solids density, up to 50% solids
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Process Targets - Produce water low in TSS
• Polymer added to each thickener– 6-7 gallons per day of neat polymer consumed– Visual inspection of settling characteristics, periodic settling tests
• All water passes through Multi-Media Filters prior to leaving the plant• Online sample stream constantly measured for turbidity• Filter influent grab samples measured at least daily for turbidity
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Process Targets - Add soda ash to reduce the Ca2+ level
• With high SO42- and Ca2+, there is a gypsum precipitation risk
– After adding lime, Ca2+ levels are >700 mg/l– Target given at Ca2+ � 470 mg/l to ensure no gypsum precipitation in
pipeline• Based on a model, and will vary seasonally• Planning to insert scale indicators
– Add soda ash:
Na2CO3 + Ca2+ � 2Na+ + CaCO3�
– Soda ash requirement has dropped from 7.5 to 4.5 lbs/1,000gal (40%) with reduction in pH from 9.0 to 8.7
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Process Targets - Keep the Sodium Adsorption Ratio (SAR) low
• High SAR poor for irrigation practice• Blended CAP/RCM maximum limit of SAR = 8.0• Lowering Ca2+ requires 2x Na+
• Add enough Na+ to lower Ca2+, but not so much that SAR > 8.0• Measure the Ca2+ with HACH kit twice per shift to maintain 470g/l
])[]([2/1][
MgCa
NaSAR
+=
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Monitoring Water Quality
• Plant water sampling– Daily and weekly composites sent for analysis
• Online water analysis– At the WTP – Data available at plant
• From sample loop on the effluent: pH, Cond., NTU, Temperature
– At NMIDD – Data available on website• Vault – Our system: Temp., Cond (TDS), pH• Upstream – CAP canal: Temp., Cond (TDS), pH• Downstream – CAP canal: Temp., Cond (TDS), pH
• Soil Analysis– Quarterly analysis from irrigated fields
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Plant Performance – Water Quality
Water Treatment Plant Performance - Water ChemistryConstituent (all mg/l unless noted) Typical Influent Typical Effluent Targets
Ca 515 455 < 700
Mg 475 295 < 400
Na 152 458 < 700
SO4 3810 3300 < 4500
TDS 5420 4700 < 6300
Alk. as CaCO3 264 18.7 < 50
Chloride 23.8 23 < 60
TSS 41.8 0.1 < 10
Cond. (µs/cm) 4680 4550 < 9800
SAR (unitless, no blend) 2.3 8.2 -
SAR (unitless, with 10:1 CAP blend) 3.8 5.1 < 8
pH 5.7 - 5.9 8.2 - 8.4 8.0 - 9.5
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Plant Performance – Water Quality
Water Treatment Plant Performance - Dissolved Metals
Constituent (all mg/l) Typical Influent Typical Effluent Targets
As 0.041 0.002 0.01
Cu 0.01 0.01 0.02
Fe 94.1 0.09 0.2
Mn 80.8 0.01 2.0
Ni 0.11 0.02 0.07
Zn 53.1 0.02 0.05
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Plant Achievements
• Total gallons treated and delivered: 500,000,000• Designed capacity of 2,500 gpm can be sustained• Stored sludge density is 40-50% solids
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Water Treatment Plant Statistics
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Looking Forward
• Winter downtime and fluctuating flows– Complete big jobs before next irrigation season
• Potential to increase plant throughput– ‘B’ Turnout– West-side of mine workings
• Potential to lower pH to 8.5– Need to establish longer success and review soil samples
• Keep a close eye on influent chemistry• Solve VFD issues on Shaft 9 pumps
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