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


The Mining Life Cycle


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


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

Types of Water Impacts on Mining


• 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)


• Integrated Water Quality Management Model (DWS, 2008)



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.



• 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



• 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)


• 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


• 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).



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



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



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.


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 Scheduling & Budget

Development

Groundwater Numerical Modelling

Mine Planning


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



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


Water Treatment Solutions


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


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


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


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

[email protected]

www.impulsewater.co

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