An introduction to and overview of Shangoni s Approach By Nico Brits

Transcription

1 Water Conservation and Demand Management Strategy An introduction to and overview of Shangoni s Approach By Nico Brits

2 Overview Background Introduction to WC/WDM Guidelines Advantages of WC/WDM Plan WC/WDM Plan Steps for Implementation Outputs of WC/WDM Strategy

3 Introduction to WC/WDM Guidelines There are two WC/WDM guidelines: Department of Water and Sanitation, June Water Conservation / Water Demand Management Implementation Guideline for the Mining Sector. Department of Water and Sanitation, June Targets for Water Conservation / Demand Management in the Mining Sector.

4 Advantages of Compiling a WC/WDM Plan Provide opportunity to discuss water conservation issues at operations and to formally document strategies. All new Water Use Licenses (WUL s) require development of WC/WDM plans and annual updates. Being pro-active for future legislative changes (GN704).

5 WC/WDM Plan Steps for Implementation 1. Summary water balances 2. Calculate Water Use Efficiency Indicators (WUE) 3. Identify WC/WDM strategies (Workshop) 4. Calculate changes to WUE indicators based on strategies proposed 5. Assign costs to strategies 6. Rank all strategies 7. Select combination of strategies for implementation

6 Step 1 - Summary Water Balances Four summary water balances are developed 1. Total Mine 2. Mining operations 3. Beneficiation plants 4. Residue disposal

7 Step 2 - Water Use Efficiency Indicators Water use efficiency (WUE) performance indicators Total water use Consumptive water use Total water use efficiency per production measure (m3 per tonne of ore mined {ROM}) Consumptive water use efficiency per production measure (m3 per tonne of ore mined{rom}) Percentage of the total volume of wastewater generated that is not reused (%) Water recycling ratio (%)

8 Results Compared with Benchmark

9 Step 3 - Identification of Potential WC/WDM Practises Based on the summary water balances and WUE indicators, strategies are formulated by means of a onsite WC/WDM workshop 1. Summary water balances are presented and discussed 2. WUE indicators are presented and discussed 3. Practical and implementable strategies (Step 3) 4. Potential WUE changes for WC/WDM strategies (Step 4) 5. Discuss costs associated with implementation (Step 5) WC/WDM Technical Report is compiled to define and document above process

10 Example of WC/WD Workshop outputs No. Option Assumptions 1 Water balance update (including the installation of a telemetric system and level control). 2 Implement storm water management plan 3 Quantify the water losses at the Discard Dump. 5 Fill point losses Construct concrete slabs with containment infrastructure at 6 main filling points to collect water spillages. Reduce 50% of unspecified sinks All affected storm water (100%) currently not recovered will be contained. 50% of the recovered water will be re-used with the remaining 50% lost as evaporation and seepage. All unspecified sinks associated with the residue disposal balance will be removed. However, it is assumed that a significant fraction (60%) will still be lost as seepage or evaporation. Dust suppression usage will reduce by 2%. 6 Fill point losses Repair leaking tanks. Dust suppression usage will reduce by 3%. 7 Filling point losses Implement RFID project. Dust suppression usage will be reduced by 5%. 8 Install infrastructure to pump water from pit sump to plant for re-use. 10 Construct new return water dam. 95% of water collected in the pit sump will be reused in the plant Reduce unspecified sinks at residue deposits by 10%. 11 Update flood risk management plan. Reduce unspecified sinks with 10% Description Total water input Consumptive use Units m 3 /year m 3 /t % Saving m 3 /year m 3 /t % Saving Current situation Option Water balance update 1 (including the installation of a telemetric system and % % level control) 2 Implement storm water management plan % % 3 Quantify the water losses at the Coarse Residue Dump % % Fill point losses 5 Construct concrete slabs at 6 main filling points to % % collect water spillages 6 Fill point losses Repair leaking tanks % % 7 Filling point losses Implement RFID project % % Install infrastructure to 8 pump water from pit sump % % to plant for re-use 10 Construct new return water dam % % 11 Update flood risk management plan % % No. Option Net Present Cost (NPC) Cost Estimate (R Million) 1 Water balance update (including the installation of a telemetric system and level control) Implement storm water management plan Quantify the water losses at the Coarse Residue Dump Fill point losses Construct concrete slabs at 6 main filling points to collect water spillages Fill point losses Repair leaking tanks Filling point losses Implement RFID project Install infrastructure to pump water from pit sump to plant for re-use Construct new return water dam Update flood risk management plan 0.3

11 Step 6 & 7 Rank Options & Select Combinations Focus on: Risk rating Priority of action Control effectiveness Return on investment Description Consumptive WUE Indicator Costs Cost Effectiveness Ranking Units m 3 /year m 3 /t % R/m 3 /annum Rands x 10 6 Saving saved Current situation Option Water balance update (including the 1 installation of a % 2.32 R12.04 Short term telemetric system and level control) Implement storm 2 water management % R Medium term plan Quantify the water 3 losses at the Coarse Residue Dump % 5.5 R47.56 Short term Fill point losses Construct concrete 5 slabs at 6 main filling points to collect water spillages % 6 R Short term Fill point losses Repair leaking tanks % 3 R33.72 Long term Filling point losses Implement RFID % 2.5 R16.86 Long term project Install infrastructure to pump water from pit sump to plant for reuse % 0.5 R6.88 Medium term Construct new return water dam % 75 R Medium term Update flood risk management plan % 0.3 R10.38 Short term

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