IMPROVING WATER MANAGEMENT IN THE MINING SECTOR … content... · improvement of water management...
Transcript of IMPROVING WATER MANAGEMENT IN THE MINING SECTOR … content... · improvement of water management...
IMPROVING WATER
MANAGEMENT IN THE MINING
SECTORPRESENTED BY: MATTHEW DAMHUIS
DHI-SA 2016 ANNUAL CONFERENCE
IMPULSE WATER (PTY) LTD
• The Mining Life Cycle
• Types of Water Impacts from Mining
• Types of Water Impacts on Mining
• Current Mine Water Management Practices (RSA)
• Current Mine Water Management Practices (Africa)
• Potential Solutions for Improving Mine Water Management
Overview
DHI-SA 2016 ANNUAL CONFERENCE
The Mining Life Cycle
DHI-SA 2016 ANNUAL CONFERENCE
Exploration & Construction
Phases
Operational Phase
Closure & Post-Closure Phases
• Exploration drilling
• Resource Determination and Modelling
• PFS/BFS
• Initial Mine Planning
• Construction (Camp, Plant, Mine etc.)
• Rehabilitation of mined land
• Deconstruction of plant, camp etc.
• Care and maintenance of key
infrastructure
• Ore Extraction
• Processing
• Sale to Market
• Mine expansion
• Waste Generation
Types of Water Impacts from Mining
DHI-SA 2016 ANNUAL CONFERENCE
http://www.environment.co.za/acid-mine-drainage-amd http://news.discovery.com/earth/one-cent-blocks-fishes-sense-of-scent-130705.htm
http://earthlife.org.za/campaigns/acid-mine-drainage/ Google Earth Imagery
https://en.wikipedia.org/wiki/Acid_mine_drainage
Picture Credits
2003 2015
• Principle legal framework for compliance (RSA)
• Constitution of the Republic of South Africa, 1996 (Act 108 of 1996)
• National Environmental Management Act (NEMA) (Act 107 of 1998)
• The Minerals and Petroleum Resources Development Act (MPRDA) (Act
28 of 2002)
• National Water Act (Act 36 of 1998)
• Various DWS Water Management Policies & Strategies (e.g. NWRS,
CMS, WC/WDM etc.)
Mine Water Management Practices (RSA)
DHI-SA 2016 ANNUAL CONFERENCE
• Integrated Water Quality Management Model (DWS, 2008)
Mine Water Management Practices (RSA)
DHI-SA 2016 ANNUAL CONFERENCE
Mine Plan
Process Plant
Water
Requirements
Stormwater
Management
Groundwater
Management
Waste
ManagementGeochemistry
INTEGRATED WATER MANAGEMENT MODEL
Mine Water and Salt Balance
IWWMP
• Challenges in the South African Mining Environment
• South Africa is a water-scarce country, thus availability of water for mining is limited
and impacts potentially severe
• Mine water management generally reactive rather than proactive
• Water-related issues not always considered in early stages of mine planning and
design
• South Africa’s mining industry is older than its management legislation and
frameworks. Thus the majority of issues faced by the country are due to older,
abandoned mines. Auditor General (2009) estimated 5’906 abandoned mines in
RSA, CGS estimated the rehabilitation bill would be ~R 30 billion of which ~R 28,5
billion would be to rehabilitate only 1’730 “high-risk” mines.
Mine Water Management Practices (RSA)
DHI-SA 2016 ANNUAL CONFERENCE
• Challenges in the South African Mining Environment (cont’d)
• Most RSA mines in the operational or closure phase
• Abandoned, flooded mines near to operational mines, potentially contributing
to cumulative impacts at the site
• Baseline conditions for the site would be impacted already
• Unrealistic RQO’s set in some instances, where the natural, background water
qualities are not taken into account (e.g. Steelpoort area, Waterberg area)
• Any updates would need to consider changes to the current operational
philosophy at the site, potentially resulting in economic impacts for the mine
Mine Water Management Practices (RSA)
DHI-SA 2016 ANNUAL CONFERENCE
• Generally reactive management
• Limited legislation for water management
• Mine compliance is based on internal obligations, e.g. IFC standards or
equator principles for listed companies
• Uncertain regulatory climate, thus capital expenditure is limited to
essentials only
• Lack of environmental understanding (e.g. aquifer potential,
river flow regimes etc.)
Mine Water Management Practices (Africa)
DHI-SA 2016 ANNUAL CONFERENCE
• Soni & Wolkersdorfer (2016) listed the following issues as essential for the
improvement of water management in the mining sector:
1. Integrated environmental planning
2. Reliable mine water technology and mine water management
3. Proactive management of water quality
4. Increase the level of detail in water-related studies early in the operational phase
5. Reduce the oxidation of tailings and leaching
6. Mine water treatment solutions should be applied whenever economically viable
7. Pit lake development in post-closure is an effective and pragmatic end use for mine
water, with sufficient stakeholder engagement and public acceptance
Solutions for Improving Mine Water Management
DHI-SA 2016 ANNUAL CONFERENCE
• Proactive Water Management can be achieved through theimplementation of an effective, realistic water management planfor the site. The Water Management Plan should be discussed inthe following sections:• Objectives;
• General Approach; and
• Water Management Controls (incl. embedded controls and mitigation measures).
Solutions for Improving Mine Water Management
DHI-SA 2016 ANNUAL CONFERENCE
Issue/Component Objective Control Measure
Co
nst
ruct
ion
Op
era
tio
nal
Clo
sure
Emb
ed
de
d M
anag
em
en
t
Mit
igat
ion
Un
exp
ect
ed
Eve
nt
Training and Awareness
Comply with
Relevant
Standards and
Legislation
Make all employees aware of:
water conservation/water demand management
water pollution avoidance and minimization measures
reporting procedure and registry of incidents
× × × ×
General Management Controls
Mine Water Management
• Automated monitoring networks can be initiated at the site where data is
transmitted to a central electronic database that is accessible to the on-site
and head office personnel, as well as I&AP’s at the site
• This allows for a secured, regular collection and transmission of data
between all stakeholders at the site (e.g. mine staff, government bodies,
surrounding water users etc.)
• The monitoring network database can be programmed to send alerts when
certain parameters are exceeded (e.g. river flow rates, water levels etc.)
• Allowing for a proactive response to mitigate and manage impacts
Solutions for Improving Mine Water Management
DHI-SA 2016 ANNUAL CONFERENCE
The current communication between mine planning &
scheduling and groundwater modelling is time consuming and
allows for human error during translation, with little
communication between the mine plan and groundwater model
Mine Planning Integration with Groundwater Modelling
Mine Design & Scheduling
Data Processing & Preparation
Numerical Groundwater
Modelling
DHI-SA 2016 ANNUAL CONFERENCE
Mine Planning Integration with Groundwater Modelling
The current method does not allow the mine to adapt to water
increases with confidence, which potentially results in high OPEX
costs relatively early in the LOM.
DHI-SA 2016 ANNUAL CONFERENCE
Through integration of the mine planning and groundwater
modelling processes, the mine may be proactive in its approach
to dewatering planning and avoid high capital costs by allowing
dewatering to be included in the operations budget when the
mine is profitable
The integration process also shortens the groundwater modelling process, allowing for continuous model updates without high
project costs
Mine Planning Integration with Groundwater Modelling
Mine Scheduling & Budget
Development
Groundwater Numerical Modelling
Mine Planning
DHI-SA 2016 ANNUAL CONFERENCE
By allowing the mine schedule to adapt to groundwater inflow
conditions the OPEX for dewatering follows a more steady
trend, allowing the mine to remain profitable and dry
Mine Planning Integration with Groundwater Modelling
DHI-SA 2016 ANNUAL CONFERENCE
Geochemical studies and classification of waste material should be completed in the early phases of the LOM
Appropriate waste storage facility liner should be installed during the construction phase and appropriate emergency response measures identified in the site water management plan (e.g. spill response procedures)
Where possible, concurrent rehabilitation of mining areas and waste disposal facilities should take place (e.g. contouring and vegetation of TSF walls)
Wet beach areas limited at the TSF, where water is reclaimed by the processing plant
Reduction of Oxidation and Leaching from Waste Storage Facilities
DHI-SA 2016 ANNUAL CONFERENCE
Water Treatment Solutions
DHI-SA 2016 ANNUAL CONFERENCE
Treatment Technology
Contaminant of Concern
Arsenic Copper LeadOther Heavy
MetalsFluoride Nitrate
Activated Alumina X S X
Granular Activated Carbon S
Distillation X X X X X
Anion Exchange X S X
Cation Exchange X X S
Ozonation
Reverse Osmosis X X X X X X
Other Adsorption Media X
Electrodialysis X X X
Ultrafiltration
Ultraviolet Light
Treatment solutions can be fully tailored and designed to meet the client requirements and budgetary needs. Some of the customisation options include:
◦ Treatment solutions can be fully containerised to allow mobility during operations
◦ Various treatment configurations can be combined to allow for the entire project objective to be met
◦ Sustainable power options can be investigated for the treatment solutions to allow minimal power
requirements
Pit Lake Formation
1) Natural Environment
2) Mine Philosophy
3) Natural Processes
4) Natural & Management
5) Management
6) Results
1
2
3
4
5
6
DHI-SA 2016 ANNUAL CONFERENCE
After Castendyk & Eary, 2009.
Pit Lake Formation: Water Treatment
Pump Treated
Water Back into
Epilimnion.
Abstract Contaminated
Water from Hypolimnion
for Treatment.
Pump
Pontoon
As Treated water gets pumped back into
pit lake, the Epilimnion layer is expanding
downwards, replacing Hypolimnion Layer.
• Pit Not Dewatered
• Pit Stability remains in place
• AMD Process
DHI-SA 2016 ANNUAL CONFERENCE
After Castendyk & Eary, 2009.
• Auditor-General South Africa, 2009. Report of the Auditor-General to Parliament
on a performance audit of the rehabilitation of abandoned mines at the
Department of Minerals and Energy.
• Castendyk, D.N. and Eary, L.E., 2009. Mine Pit Lakes: Characteristics, Predictive
Modeling and Sustainability (Volume 3). SME, Colorado, USA.
• Department of Water & Sanitation (DWS), 2008. Best Practice Guideline H1:
Integrated Mine Water Management. Government Printers, Pretoria, South Africa.
• Soni, A.K. & Wolkersdorfer, C., 2016. Mine water: policy perspective for improving
water management in the mining environment with respect to developing
economies. International Journal of Mining, Reclamation and Environment, 30:2,
115-127, DOI: 10.1080/17480930.2015.1011372
References
DHI-SA 2016 ANNUAL CONFERENCE
Thank You
JOHANNESBURG
The Pivot - Ground Floor, Block E
No. 1 Montecasino Boulevard
Fourways, Gauteng
Contact:
Matthew Damhuis
Tel: +27 11 568 2100
Mobile: +27 82 684 0801
www.impulsewater.co