THE EXPLOITATION OF BORROW PITS FOR SUPPLY OF MATERIALS FOR REGRAVELLING AND MAINTENANCE OF GRAVEL ROADS IN THE KNYSNA LOCAL MUNICIPALITY, EDEN ...
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Report No: xxxx/402828
THE EXPLOITATION OF BORROW PITS
FOR SUPPLY OF MATERIALS FOR
REGRAVELLING AND MAINTENANCE
OF GRAVEL ROADS IN THE KNYSNA
LOCAL MUNICIPALITY, EDEN
DISTRICT MUNICIPALITY
GENERIC ENVIRONMENTAL MANAGEMENT
PROGRAMME
February 2012
Aurecon (Pty) Ltd Nadeson Consulting Services (Pty) Ltd
Aurecon Centre 22 Riebeek Street
1 Century City Drive P O Box 51121
Century City V & A Waterfront
7441 8002
Tel: (021) 526 6035 Tel: (021) 418 4988
Fax: (021) 526 9500 Fax: (021) 419 5187
Email: simon.vanwyk@aurecongroup.com Email:fsamaai@nadeson.net
Dept. Transport & Public Works: PGWC
P O Box 2603, Cape Town, 8000
Tel: (021) 483 2020
Fax: (021) 483 2205
Email: llewellyn.truter@pgwc.gov.zaBORROW PITS FOR KNYSNA LOCAL MUNICIPALITY ROADS REGRAVELLING: EMPROG Page 2
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PREAMBLE
This document serves as a generic Environmental Management Programme (EMProg)
for the exploitation of borrow pits proposed for use in the regravelling and maintenance
of gravel roads in the Knysna Local Municipality, within the Eden District Municipality.
This is accompanied by various supplementary reports which deal with specific borrow
pit sites and regravel sections within the local municipality. The Environmental
Discipline Group of Aurecon Consulting Services was appointed to compile this EMProg
on behalf of the proponent, the Provincial Government of the Western Cape (PGWC).
This EMProg endeavours to present a best practice approach to the environmental
reporting for material sourcing associated with gravel roads. Accordingly, it has been
compiled in accordance with the Minerals and Petroleum Resources Development Act
(No 28 of 2002), the National Environmental Management Act (No 107 of 1998), the
National Heritage Resources Act (No 25 of 1999), discussions with the Department of
Mineral Resources (DMR), the Provincial Government of the Western Cape’s (previously
Western Cape Provincial Administration: WCPA’s) “Manual for the Identification,
Development, Operation and Closure of Gravel materials Sources” (WCPA, 2006), as
well as the guidelines for small mining activities as prescribed by the DMR’s Aide-
Memoir for the Preparation of Environmental Management Programme Reports for
Prospecting and Mining, 1992.
Since the utilisation of material sources is in essence about the management of assets
and risks, the approach adopted in this EMProg is underpinned by a risk management
philosophy. Moreover, particular cognisance has been taken of the greater emphasis
that the Minerals and Petroleum Resources Development Act places effective
stakeholder engagement.
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REPORT CONTROL SHEET
CLIENT: Provincial Government Western Cape: Department of Transport
and Public Works
CLIENT REPRESENTATIVE: Mr Llewellyn Truter
PROJECT NUMBER: 402828
REPORT TITLE: The exploitation of borrow pits for supply of material for
regravelling and maintenance of gravel roads in the Knysna
Local Municipality, Eden District Municipality: Environmental
Management Programme.
AUTHOR(S): S Van Wyk, K King and Z Els
REPORT STATUS: Draft
PREPARED BY: K King and Z Els
REPORT NUMBER: xxxx/402828
DATE: January 2012
Author(s):
KEN KING ZELDA ELS
Environmental Practitioner: Environmental and Advisory Risk Consultant: Environmental and Advisory Services
Services
SIMON VAN WYK (Pr. Sci. Nat)
Environmental Practitioner: Environmental and Advisory
Services
Approved by:
DR ELRETHA LOUW (Pr.GISc)
___________________________
TECHNICAL DIRECTOR
Environmental and Advisory Services
This report is to be referred to in bibliographies as: Aurecon (2012) The exploitation of borrow
pits for supply of material for regravelling and maintenance of gravel roads in the Knysna Local
Municipality, Eden District Municipality: Environmental Management Programme. Report no.
xxxx/402828
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CONTENTS
Preamble ........................................................................................................................... 3
Contents ............................................................................................................................ 7
List of Figures .................................................................................................................... 9
List of Tables ..................................................................................................................... 9
List of Annexures ............................................................................................................... 9
Abbreviations ..................................................................................................................... 9
1 INTRODUCTION ............................................................................................................. 11
1.1 Background ............................................................................................................. 11
1.2 Purpose of this document........................................................................................ 11
1.3 Document structure ................................................................................................. 12
2 DETAILED DESCRIPTION OF THE PROJECT .............................................................. 15
2.1 Mining objectives .................................................................................................... 15
2.2 Details of the applicant ............................................................................................ 15
2.2.1 Mine owner & manager............................................................................. 15
2.2.2 Mineral rights holder ................................................................................. 16
2.2.3 Applicant for mining approval .................................................................... 16
2.3 Project description .................................................................................................. 17
2.3.1 The regravelling operations ...................................................................... 17
2.3.2 The mining activities ................................................................................. 17
2.3.3 Benefits of the project ............................................................................... 19
2.4 The Consideration of Sources for the provision of materials REQUIRED ................ 20
2.5 Proposed timetable, duration & sequence ............................................................... 21
2.6 Financial provision .................................................................................................. 21
3 DESCRIPTION OF THE PRE-CONSTRUCTION ENVIRONMENT ................................. 23
3.1 Geology and soils ................................................................................................... 23
3.2 Climate.................................................................................................................... 23
3.3 Land capability ........................................................................................................ 24
3.4 Land use ................................................................................................................. 24
3.5 Vegetation............................................................................................................... 25
3.6 Animal life ............................................................................................................... 26
3.7 Surface and ground water ....................................................................................... 26
3.8 Air quality ................................................................................................................ 26
3.9 Noise ...................................................................................................................... 27
3.10 Sites of archaeological & cultural interest ................................................................ 27
3.11 Visual aspects ......................................................................................................... 27
3.12 Access .................................................................................................................... 27
3.13 Traffic safety ........................................................................................................... 28
3.14 Regional socio-economic structure ......................................................................... 29
3.15 Interested & affected parties ................................................................................... 30
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4 ASSESSMENT PHILOSOPHY & METHODOLOGY ....................................................... 33
4.1 Introduction ............................................................................................................. 33
4.2 Risk management ................................................................................................... 33
4.3 Overview of risk assessment tool ............................................................................ 36
4.3.1 Risk register ............................................................................................. 36
4.3.2 Evaluation of risk ...................................................................................... 36
4.3.3 Mapping of risk ......................................................................................... 39
4.3.4 Treatment of risk ....................................................................................... 40
5 GENERIC EMP FOR PREPARATION, MINING AND CLOSURE ................................... 45
5.1 Introduction ............................................................................................................. 45
5.2 Generic environmental management requirements for borrow pits .......................... 45
5.3 Mining & closure objectives ..................................................................................... 46
5.4 Proposed approach to mining & rehabilitation ......................................................... 47
5.4.1 Preparation / Operation ............................................................................ 47
5.4.2 Mining of material ..................................................................................... 49
5.4.3 Rehabilitation ............................................................................................ 50
6 SUMMARY AND RECOMMENDATIONS ....................................................................... 53
7 REFERENCES ................................................................................................................ 55
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LIST OF FIGURES
Figure 3.1: Employment in the Overberg DM is diversified (Overberg DM, 2002) ..................... 30
Figure 4.1: Diagrammatic illustration of the risk assessment process adopted for the current
investigation (Western Cape Provincial Administration, 2006). ................................................. 35
LIST OF TABLES
Table 3.1: Population figures for the Overberg District Municipality (Statistic South Africa, 2001).
................................................................................................................................................. 29
Table 4.1: Borrow pit risk register, summarises the various risks assessed for each borrow pit.
................................................................................................................................................. 36
LIST OF ANNEXURES
Annexure A: Risk register
Annexure B: Extracts from the PGWC Operational Manual (WCPA, 2006)
B1: Chapter 6: Basic Borrow Pit Management Requirements
B2: Chapter 7: Closure of Depleted Borrow Pits
B3: Chapter 8: Reporting
Annexure C: Operational Manual Sheets (WCPA, 2007)
ABBREVIATIONS
DEA&DP Department of Environmental Affairs and Development Planning
DMR Department of Mineral Resources
EMP Environmental Management Plan
EMProg Environmental Management Programme
M&PRDA Minerals and Petroleum Resources Development Act
EDM Eden District Municipality
PGWC Provincial Government Western Cape
WCPA Western Cape Provincial Administration
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1 INTRODUCTION
1.1 BACKGROUND
Environmental Services of Aurecon South Africa was appointed by the Provincial Government
of the Western Cape (PGWC) to facilitate compliance with the applicable environmental
legislation on behalf of the PGWC: Department of Transport and Public Works. Specifically,
Aurecon Environmental Services' Scope of Work entailed the compilation of an Environmental
Management Programme (EMProg) as the basis for seeking authorisation from the Department
of Mineral Resources (DMR) for various material sources identified for use in proposed
maintenance and regravelling projects.
1.2 PURPOSE OF THIS DOCUMENT
As per the requirements of the Minerals and Petroleum Resources Development Act (M&PRDA)
(No 28 of 2002), all mining activities, including the extraction of material from borrow pits and
quarries, require authorisation from the Department of Mineral Resources (DMR). As per the
provision of Section 106(1) of the Act, on 25 June 2004 the Minister of Minerals and Energy, by
notice in Government Gazette No. 26501, has exempted various organs of state from the
provisions of sections 16, 20, 22 and 27 of the Act in respect of any activity to remove any
mineral for the construction and maintenance of dams, harbours, roads and railway lines and for
purposes incidental thereto. The exempted organs of state are as follows:
Department of Water Affairs and Forestry;
National Parks Board;
South African National Roads Agency Limited;
National Ports Authority of South Africa;
Spoornet; and
Provincial Governments.
In terms of this exemption, where the PGWC is undertaking the maintenance/ upgrading of
roads under its control, no application needs to be submitted for a mining right or permit.
However, as per the provisions of Section 106(2) of the Act, they are required to prepare and
submit an EMProg to DMR for their approval, prior to the extraction of any material from a
proposed borrow pit or quarry, hence the submission of this and supplementary documents.
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1.3 DOCUMENT STRUCTURE
Material sourcing for road construction and maintenance is distinctly different from large-scale
mining. Whilst the potential for significant environmental impacts associated with the operation
of borrow pits is patent, the spatio-temporal extent and scale of these impacts are very different
from that encountered in larger commercial mining operations. This notwithstanding, since
statutory environmental reporting has grown out of the framework established for larger mining
activities, EMProgs for borrow pits have historically tended to be capacious and vague or
imprecise documents, ill-suited to scale or nature of activities they are intended to address. As
such, these EMProgs have failed to highlight adequately the key environmental issues, and thus
have become mediocre instruments of informed decision-making. Recognising the historic
weaknesses, Aurecon has adopted a new approach to the compilation of EMProgs associated
with material sources for road construction and maintenance. This approach is based upon the
“Manual for the Identification, Development, Operation and Closure of Gravel Materials
Sources” or “Operational Manual” recently compiled by the PGWC (WCPA, 2006) and included
in part in Annexure A of this report.
As outlined in the Operational Manual, the utilisation of materials sources is in essence about
the management of assets and risk, and hence the approach adopted to the compilations of the
EMProg is founded on a risk management philosophy. Specifically this document in comprised
of the following parts:
Chapter 1, this introductory chapter, provides the background to the application and the
need for and structure of the EMProg;
Chapter 2 provides a detailed overview of the road regravelling project, including details of
the applicant, the consideration of material sources, and the calculation of financial
provision.
Chapter 3 provides a description of the environment that could be affected by the proposed
activities;
Chapter 4 provides an overview of the methodology employed in the identification,
assessment and mitigation of potential environmental risk;
Chapter 5 presents a generic EMprog for the preparation, mining and closure of borrow pits.
Chapter 6 provides a brief summary of the report.
Chapter 7 lists the references consulted in the preparation of this report.
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2 DETAILED DESCRIPTION OF THE PROJECT
2.1 MINING OBJECTIVES
In committing to the responsible and sustainable utilisation of materials for the maintenance of
gravel roads, the PGWC articulated the following strategic vision in the Operational Manual
(Western Cape Provincial Administration, 2006):
“Extract suitable quality material from proven, authorised borrow areas for the
maintenance of gravel roads on a sustainable basis”.
In responding to this vision, the PGWC have further articulated the following Mining
Objectives for all of the materials sources under their control:
Optimising the yield and economic viability;
Enhancing the technical efficiency of extraction;
Optimising the operational efficiency;
Minimizing adverse environmental impacts;
Promoting health and safety;
Maintaining legal and technical compliance at the highest level;
Mitigating risks to all stakeholders, including landowners, affected parties and local
and provincial authorities;
Meeting budget constraints;
Honouring conditions of agreement with landowners; and
Assuring that the land is restored to beneficial use thereafter.
These mining objectives, which are encapsulated in the phrase “Mine with the end in mind”,
have become a fundamental informant of the PGWC’s approach to the identification, operation
and closure of material sources used in the maintenance of the gravel road network under their
control. The broad objectives outlined above are augmented by site specific Closure Objectives
in the accompanying report(s).
2.2 DETAILS OF THE APPLICANT
2.2.1 Mine owner & manager
The Eden District Municipality (EDM) will be undertaking the work on behalf of the PGWC.
Where the proposed sites are situated on private property, the land will either be expropriated
by the PGWC or a formal agreement will be entered into between the landowner and the
PGWC. Even where land is expropriated, the PGWC does not take transfer of the property, and
the EDM would then manage the site until decommissioning and closure. Pursuant to achieving
closure in terms of the M&PRDA the land would revert to the landowner.
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2.2.2 Mineral rights holder
According to the M&PRDA, mineral resources are in the custodianship of the State. However,
the PGWC would temporarily acquire the right to mine the borrow pits, subject to approval by
the DMR and the successful temporary expropriation of the site.
2.2.3 Applicant for mining approval
As the exempted organ of state the PGWC is the applicant for the proposed borrow pit
operations. Contact details for the Applicant are provided below.
Provincial Government Western Cape: Department of Transport and Public Works
Contact person: Mr Llewellyn Truter
Postal address: PO Box 2603, Cape Town, 8000
Tel: (021) 483 2020
Fax: (021) 483 2205
Email: llewellyn.truter@pgwc.gov.za
The contact details for the Engineering consultants are as follows:
Aurecon South Africa: Transportation
Contact person: Mr Dave Rose
Street address: 1 Century City Drive, Century City, 7441
Postal Address: PO Box 494, Cape Town, 8000
Tel: (021) 526 9400
Fax: (021) 526 9500
E-mail: david.rose@aurecongroup.com
The contact details for the Environmental consultants are as follows:
Aurecon South Africa: Environmental Services
Contact person: Mr Simon van Wyk
Street address: 1 Century City Drive, Century City, 7441
Postal Address: P O Box 494, Cape Town, 8000
Tel: (021) 526 6035
Fax: (021) 526 9500
E-mail: simon.vanwyk@aurecongroup.com
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2.3 PROJECT DESCRIPTION
2.3.1 The regravelling operations
For a gravel road to be able to carry traffic safely and effectively, an upper layer of gravel,
known as a wearing course, which meets specific technical requirements, has to be placed on
the prepared roadbed. With time, the wearing course is eroded away by both traffic and the
elements. This wearing course needs to be replaced in order to continue to deliver a safe and
functional surface to the road user. As outlined in Chapter 1, Environmental Services of
Aurecon was appointed by the PGWC to provide professional services for the regravelling of
sections of minor, divisional, main and trunk roads throughout the Western Cape. Geotechnical
investigations were carried out by Aurecon (borrow pit exploration) and Outeniqua Lab
(laboratory testing). The road sections highlighted for regravelling are specified in the various
supplementary reports which accompany this generic EMProg. In addition to this, the borrow
pits identified will be used as sources of material for ongoing maintenance work and for the
repair of roads during emergency situations as a result of, for example, flooding.
During re-gravelling, the existing road surface is shaped (if the density of the layer complies with
the specification) or ripped, shaped and re-compacted to ensure easy drainage of surface
water. Side drains are reshaped to further facilitate drainage and increase the longevity of the
road. Target thickness for the new wearing course is 150 mm for Divisional Roads and 140 mm
for Main Roads.
Implementation of these regravelling and maintenance activities would obviously necessitate
the extraction of suitable materials (gravel wearing course, fines and fill), meeting the
appropriate technical requirements, from identified material sources. Suitable gravel is not
always readily available, and has to be sought. Details of the various material sources identified
and assessed for specific regravel;ling projects or general maintenance work are discussed in
the supplementary reports which accompany this generic EMProg.
2.3.2 The mining activities
This section provides a generic overview of the mining activities typically associated with the
operation of borrow pits. These are supplemented by recommendations and approaches
specific to each borrow pit assessed in the accompanying report(s).
a) Site infrastructure
i) Access
Generally, no new roads would have to be constructed to provide access to the
proposed sites. Where additional roads are necessary, these are clearly marked on
the mine plans. The borrow pits are accessed either directly off minor, main, or
divisional roads or via existing access tracks. Wherever necessary, access tracks
would be repaired or upgraded and maintained to facilitate access by haulage
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vehicles. The borrow pits and access tracks would be fenced for the duration of the
mining activities.
ii) Site infrastructure & plant
There will be no site buildings located at the borrow pit sites. Site infrastructure
would be restricted to that associated with minimal maintenance and mobile
refuelling activities of the mobile plant used to excavate and transport the procured
gravel, as well as a chemical toilet and refuse bins. All areas used for the location of
facilities at the borrow pit sites would be subject to the rehabilitation programme
outlined for each borrow pit.
On site plant would be minimal, comprised mainly of an excavator or a bulldozer, a
front-end loader and dump trucks for the transport of material. The material sources
are such that on site crushing would only be required for material obtained from
certain geological units such as Enon conglomerate, certain Karoo mudstones, and
sandstones of the Cape Supergroup. Mobile, temporary, single stage crushers will
be utilised to break oversize material down to the maximum allowable size for road
gravel, viz. 38mm. Should material need blending or breaking down, this would
occur at the mining face within the footprint of the demarcated and fenced borrow pit
area, or on the road being regravelled.
iii) Management of water & protection of watercourses
Since several of the material sources may result in the accumulation of water,
measures would need to be taken during mining operations to manage any
accumulation of water and associated erosion. This could include the installation of
semi-permanent or permanent drainage works or the implementation of a range of
erosion control measures to prevent the concentration of runoff and concomitant
erosion. Generic guidelines in this regard are provided in Chapter 5 of this
document, and site-specific guidelines in accompanying reports.
b) Site preparation
The site preparation for the borrow pits would entail the establishment of temporary site
infrastructure (where required), including fencing. Wherever possible existing
infrastructure or existing borrow pits and other disturbed areas would be utilised.
Site preparation would also involve clearing and removal of topsoil and overburden from
the area to be mined. Generic guidance in this regard is provided in Chapter 5 of this
report.
c) Site operational
Details for the development of each of the proposed borrow pits is provided in the mining
plans included in supplementary reports. Generic guidance in this regard is provided in
Chapter 5 of this report. Conceptually, the mining of each material source would entail
the following:
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i) Mining method
The borrow pits will be mechanically mined on an intermittent basis as and when
required for periods of regravelling of roads, with haulage distances restricted to less
than 15 km. Excavators and bulldozers will be used to produce gravel suitable for
wearing course material. Working faces of the borrow pit would first be ripped and
then excavated, before the excavated material is stockpiled. Stockpiled material
would be loaded onto the haulage vehicles for transport to regravelling sites.
Stockpiles will also be utilised on an intermittent basis as and when required for
maintenance and flood damage repair, in addition to their extended used during
periods of regravelling of roads. Should further processing of the material be
required (e.g. breaking down oversize material or blending with plastic fines), it
would take place at the mine face within the footprint of the demarcated and fenced
borrow pit area, or on the road being regravelled.
ii) Phases of mining
Some of the borrow pits have been identified as non-strategic “once-off” pits which
will only be utilized for the duration of the project as described. Others have been
identified as strategic sites which will be utilised over a period of several years to
provide a consistent source of material for regravelling, maintenance and
emergency projects. Mining of these sites will be phased in order to reduce the area
of exposed soil at any one time, as detailed on the mine plans. Once the required
amount of material has been mined, the worked area would be shaped, stabilised
and revegetated, thereby ensuring that the mine is worked, rehabilitated and
revegetated progressively.
iii) Transport
Excavated material would be transported via dump truck and placed alongside the
gravel roads that require maintenance or upgrade.
d) Decommissioning
During decommissioning, the working area will be rehabilitated and revegetated, as per
the approach outlined in the mining plan. It is important to recognise that the PGWC’s
liability for the site persists until such time as a Closure Certificate has been issued by
the DMR. Accordingly, once the vegetation has established, a closure report will be
submitted to DMR.
2.3.3 Benefits of the project
The material excavated from the borrow pits may be used for maintenance, the re-gravelling
(construction of a new wearing course layer), and for improvements to drainage along the
portions of gravel road requiring maintenance or improvement, as outlined in accompanying
supplementary reports. This would benefit road users and local inhabitants by minimising
maintenance-related disruptions and ensuring greater road safety and supporting the local
economy by ensuring continual access to markets etc.
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2.4 THE CONSIDERATION OF SOURCES FOR THE
PROVISION OF MATERIALS REQUIRED
The identification of potential sources of material suitable for use in the regravelling and
maintenance of gravel roads is conducted systematically. Cognisance is taken of the entire
length of the road and the length of the section(s) requiring regravelling or maintenance for
present project and potentially in future. Initially, an assessment is made of any existing borrow
pits along the road, considering the quantity of material which remains and it’s suitability for
road regravelling, the state of the surrounding environment and the degree to which the borrow
pit has revegetated, and the distance of the borrow pit from the section(s) of road requiring
regravelling.
In addition to this, several new sites which have the potential to supply gravel are identified and
visually screened in the field by an engineering geologist and environmental practitioner. An
assessment is made of: the availability and type of material, the current land use, the visual
impact of creating a borrow pit, the type and condition of vegetation on site, the potential impact
on surface water flow, and the risks to people/animals in the vicinity. This preliminary screening
phase typically results in the exclusion of 50% or more of potential sites.
Samples are taken from short-listed sites for geotechnical analysis to determine the suitability of
the material for regravelling. Should the material be suitable, the site is surveyed and a mine
plan prepared. At the same time an independent desktop heritage study consisting of
archaeological and palaeontological assessments is carried out by Vidememoria Heritage
Consultants to determine the cultural sensitivity of the site, and the findings submitted to the
governing body (Heritage Western Cape: HWC) for comment. Should further heritage studies
be requested by HWC, archaeological and/or palaeontological field assessments are then
carried out by Vidememoria, and the findings submitted to a senior council at HWC for
comment. Upon completion of the mine plan, an additional field visit to assess the
environmental impacts may be carried out.
Once a thorough environmental and heritage impact assessment has been completed and
authorisation has been obtained from HWC to exploit the pit, an environmental management
programme (EMPRog) – this report and associated supplements – is prepared. Supplements
provide a comprehensive description and assessment of the borrow pits for which mining
authorisation is sought, and a brief overview of alternative sites considered.
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2.5 PROPOSED TIMETABLE, DURATION & SEQUENCE
The proposed mining timetable, duration and sequence for borrow pits depend on the extent of
work required at the time of submission, the nature and extent of planned maintenance and
upgrade projects, and the likelihood of events such as floods, landslides etc. that could
necessitate emergency repairs at short notice. As far as possible these factors are detailed in
the accompanying report(s). Some borrow pits are highlighted as strategic material sources
which may be used over a period of several years for ongoing maintenance.
2.6 FINANCIAL PROVISION
Financial provision (surety) must be made for the closure or sudden cessation of work and for
any rehabilitation / revegetation work. The issue of financial provisions and applicability to road
maintenance activities by PGWC has been raised with DMR1, and it has been agreed that
where the road maintenance is undertaken by an independent contractor, provision for the
financial guarantees would occur via the contract.
The calculation of the financial provision below is based on the “Guideline Document for the
Evaluation of the Quantum of Closure-Related Financial Provision provided by a Mine”, the
“Official guideline as contemplated in Regulation 54(1) to the Mineral and Petroleum Resources
Development Act, 2002 (Act 28 of 2002), Revision 1.6 (7th September 2004)”, hereinafter
referred to as (DME, 2004). Under this guideline, borrow pits for the quarrying of materials
including calcrete, clays, dolerite, granite, sand and gravel, siltstone and soil are classified as
Class C mines.
The guideline specifies minimum rates per hectare for closure, depending on the environmental
sensitivity of the Class C mine area. The minimum amount for class C mines is R10,000.
Using this guideline and the area of each borrow pit, financial amounts have been calculated for
each borrow pit. This amount will be held back as retention and will only be paid out to the
contractor after an inspection by the engineer and the issuing of a Final Certificate of
Completion. The Final Certificate of Completion will not be issued before the engineer has
ensured that all the items on the defects list had been adhered to and been rectified to the set
standards and specifications.
1Correspondence between Aurecon and J.H. Briers (DMR) dated 7th May 2010 confirming that organs of state are
exempted in terms of Section 106 with regards to Sections 16, 20, 22 and 27 of the M&PRDA.
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3 DESCRIPTION OF THE PRE-CONSTRUCTION
ENVIRONMENT
This chapter provides overall general contexts of the area in which the borrow pits discussed in
accompanying reports are located. Accompanying reports which deal with specific borrow pits
contain maps illustrating the environment, vegetation topography etc.
3.1 GEOLOGY AND SOILS
The geology in the north centre of the Overberg District Municipality is dominated by shale of
the Bokkeveld Group, part of the Cape Supergroup. This formation forms rolling hills across the
large portion of the Overberg and indeed the South Cape area. Arenites of the Peninsula
Formation, Table Mountain Group (Cape Supergroup) are present in small areas in the north,
center and west of the municipality. Low lying areas adjacent to the coast are underlain by
limestone of the Bredasdorp Group. Their formation is related to sea level fluctuations during
the Cenozoic when sea levels were significantly higher than at present. Unconsolidated
superficial deposits (fluvial gravels and sands) of Quaternary age locally overlie the
aforementioned formations and groups.
Soils underlain by shales are generally silty-sandy, whereas limestone-derived soils along the
coastal platform are gritty and calcareous. The former are suitable for cultivation and are
extensively cultivated (section 3.4), whereas the latter are not.
3.2 CLIMATE
The Overberg Local Municipality is located in the southern Cape, an area largely characterised
by a Mediterranean climate comprising and cool wet winters and hot dry summers. Maximum
daily temperatures inland average 26 to 28°C in summer and 16 to 18°C in winter, while coastal
areas average 24 to 26°C and 16 to 18°C respectively (Schulze, Maharaj, Lynch, Howe, &
Melvil-Thomson, 1997). The sea provides moderating influence on the temperature and as
such the largest part of the DM is almost frost free. Frost is experienced in small areas in the
north and the high mountain peaks in the northeast occasionally receive a small dusting of snow
in winter (Overberg DM, 2004).
The largest part of the Overberg District Municipality is characterised by winter rainfall, with the
wettest months being May to October which experience an average of 40 to 60mm per month
(Schulze, Maharaj, Lynch, Howe, & Melvil-Thomson, 1997). The total annual precipitation in
this area is 400 to 600mm. The eastern part of the municipality is located in the transition
between the winter and summer rainfall areas, and consequently experiences rainfall
throughout the year, with peaks in March and August to October (Schulze, Maharaj, Lynch,
Howe, & Melvil-Thomson, 1997) (Overberg DM, 2004). Total annual precipitation here ranges
from 200 to 400mm (Schulze, Maharaj, Lynch, Howe, & Melvil-Thomson, 1997). Wind along
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BORROW PITS FOR KNYSNA LOCAL MUNICIPALITY ROADS REGRAVELLING: EMPROG Page 25
The majority of land in the Overberg District Municipality is arable, particularly that underlain by
shales of the Bokkeveld Group in the centre of the municipality. Wheat and canola are the
dominant crops being tended. Land too steep to be cultivated is often used for grazing of sheep
or cattle. Mountainous areas to the north of the Swellendam, in the northeast of the
municipality, are unsuitable for cultivation or grazing and therefore defined as wilderness.
Protected areas and nature reserves in the Mossel Bay Local Municipality include:
In the north and northeast
o Bontebok National Park
o Marloth Nature Reserve
o Langeberg West Mountain Catchment Area
o Riviersonderend Nature Reserve
In the centre and south
o Salmonsdam Nature Reserve
o Walker Bay State Forest
o Maanschynkop Nature Reserve
o Babilonstoring Nature Reserve
o Agulhas National Park
o Soetendalsvlei Nature Reserve
o De Mond Nature Reserve
o Waenhuiskrans Nature Reserve
o Quoin Point Nature Reserve
In the west
o Hottentots Holland Mountain Catchment Area
o Lebanon State Forest
o Nuweberg State Forest
o Kogelberg Nature Reserve
Accompanying reports detailing the proposed exploitation of existing or new borrow pits provide
details on the proximity of the borrow pits to these areas.
3.5 VEGETATION
Assessments of the vegetation of the materials source sites were carried out by Aurecon
environmental practitioners. Brief descriptions of the nature, density and condition of both
indigenous and alien vegetation at and around specific borrow pits were provided and are
detailed in accompanying reports. Information on the biome classification and conservation
status was obtained from the South African National Biodiversity Institute (SANBI) Geographical
Information Systems (GIS) database (SANBI, 2011); and from (Mucina & Rutherford, 2006).
Due cognisance was made of endangered or threatened vegetation units and no borrow pits
were created in or expanded into such units.
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3.6 ANIMAL LIFE
The variety of vegetation type found in the Overberg DM provides a range of habitats for several
animal species. The mountainous region of Swellendam in the northeast is home to chacma
baboons, caracal, large spotted genet and the cape leopard. The plains, which make up the
majority of the area, contain small buck such as the cape grysbok and klipspringer, grey
mongoose, and a variety of large birds including blue cranes, white storks and bustards.
Flamingoes are reputed to occasionally breed in the shallow lakes to the south of Bredasdorp.
The waters off the coast are nutrient-rich due to the meeting of the Agulhas and WHAT
currents. This provides for an abundance of diverse marine life, including whales, seals,
sharks, gulls, cormorants and gannets. These are protected in marine protected areas such as
the De Hoop MPA and Betty’s Bay MPA.
Given the inherent mobility of animals and the fact that none of the proposed borrow pits are
located within or in immediate proximity to rivers, estuaries or protected areas, animals will not
be threatened by the proposed expansion of the borrow pits as the disturbance associated with
these mining activities are very localised.
3.7 SURFACE AND GROUND WATER
The principle rivers in the Overberg DM are the Riviersonderend and Breede Rivers, the latter
of which forms the eastern border with the Eden DM. Smaller rivers include the Swart, Bot,
Onrus, Palmiet, Klein, Sondagskloof, Kars, Sout, Potbergs, Napkei and Kwassidie Rivers.
Estuaries and lakes are common along the coast, and seasonal wetlands are present locally.
The mountains in the north of the DM are important catchment areas, from which water is
diverted into the Steenbras and Theewaterskloof Dams which provide water for the Cape
Metropolitan area (Overberg DM, 2004). Smaller dams which serve as water sources for local
towns include the Buffelsjagts Dam near Swellendam and the De Bos Dam near Hermanus
(Overberg DM, 2004).
Quartzites, shales and Cenozoic sediments on the coastal plane in the south of the Overberg
DM, contain strong groundwater aquifers. Groundwater is exploited to a limited extent in some
areas. However, it is unlikely that groundwater would be affected due to the shallowness of the
borrow pits and the low risk of pollution associated with the nature of the mining activities.
3.8 AIR QUALITY
In general, the ambient air quality is good at borrow pit sites investigated. Dust derived from the
gravel roads (those being regravelled) adjacent to the borrow pits represents a minor nuisance.
Other forms of pollutant specific to any borrow pit are mentioned in accompanying reports.
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3.9 NOISE
Borrow pits located adjacent to the gravel roads being regravelled generally experience low
ambient noise levels, however these are impacted upon by intermittent passing vehicle traffic
and, locally, nearby farming activities. Noise levels will be higher during periods when the
borrow pits are being worked, however due cognisance will be taken of the location of nearby
dwellings to avoid unnecessary noise disturbances.
3.10 SITES OF ARCHAEOLOGICAL & CULTURAL INTEREST
Archaeological and cultural resources are protected by the National Heritage Resources Act
(No. 25 of 1999). Section 38 (1) (c) of this stipulates that if developments will change the
character of a site and are in excess of 5,000m2 in extent, the responsible heritage authority
must be notified and furnished with details regarding the location, nature and extent of the
proposed development. To this end, Vidamemoria heritage consultants were contracted by
Aurecon to conduct heritage, archaeological and palaeontological assessments of each borrow
pit for submission to Heritage Western Cape (HWC). These assessments by Vidamemoria and
the comment(s) from HWC are attached in full in Annexures B and C of the accompanying
reports.
3.11 VISUAL ASPECTS
The Overberg DM is visually pleasing and is dominated by rolling hills of cultivated wheat and
canola fields. These create an attractive patchwork of pastel and green shades across the
landscape in the centre of the municipality. The north, the imposing east-west trending
Langeberg Mountains dominate the landscape. These are characterised by high, rugged peaks
which rise to over 1,600m and narrow, deeply incised steep-sided gorges. The rocky coastal
areas are characterised by low-lying rocky platforms and long, narrow sandy beaches.
In the assessment of potential material sources for road regravelling or maintenance projects,
due consideration is given to the potential visual impact of proposed borrow pits and guided by
the following aspects:
Minimize negative visual impacts and maximize positive impacts
Rework existing pits left in an untidy state and rehabilitate appropriately after completion
of the work (generally with a phased approach)
Expand existing or create new pits which will retain small amounts of water and thereby
revegetate more quickly and thoroughly
3.12 ACCESS
The locations of access tracks to all borrow pits discussed are detailed on the mine plans in
accompanying reports. Most existing borrow pits have access tracks or are accessed directly
from the side of the adjacent minor, divisional, main or trunk road. Access tracks are designed
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to be as short as possible to minimize environmental disturbance, with due consideration given
to the topography, existing infrastructure and road safety concerns.
3.13 TRAFFIC SAFETY
Haulage vehicles operating on divisional roads adjacent to the borrow pits do not pose a
significant traffic hazard due to the low traffic volumes on many of the roads adjacent to which
the borrow pits are located. However, special safety precautions such as those outlined in
section 5.4.1 of will be enforced in order to minimise the risk to traffic safety. Where additional
safety measures specific to certain borrow pits are required, these are detailed in
supplementary reports discussing those borrow pits.
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3.14 REGIONAL SOCIO-ECONOMIC STRUCTURE
The Western Cape Province consists of five District Municipalities, which in turn comprise
several local municipalities plus/minus district management areas (DMAs). The Overberg
District Municipality (ODM) is located in the south of the Western Cape Province and consists of
four local municipalities (Theewaterskloof, Overstrand, Mossel Bay and Swellendam) and one
district management area (De Hoop Nature Reserve: DMA03). The Swellendam Local
Municipality (LM) consists of 7 wards (Swellendam, Barrydale, Suurbraak, Buffeljagtsrivier,
Malgas, Infanta and Stormvlei), and the Mossel Bay LM of 8 wards (Bredasdorp, Struisbaai,
Napier, Elim, Waenhuiskrans, L’Agulhas, Portem and Klipdale).
The total population of the Overberg DM in 2001 was 203,497, of which 45% reside in the
Theewaterskloof LM (Table 3.1) (Statistic South Africa, 2001). The Swellendam and Cape
Agulhas LMs are relatively sparsely populated and having a low number of households. The
population of the Overberg is growing strongly largely due to the influx of retirees and
pensioners, and migrant labourers seeking employment (Overberg DM, 2002).
Table 3.1: Population figures for the Eden District Municipality (Statistic South Africa, 2001).
Census figures indicate that in 1997/98, 35% of the Overberg population lived in rural areas and
64% in urban areas (Overberg DM, 2004). The figures for 1984 were 50.3% and 49.7%
respectively, indicating a strong trend of urbanisation. The Overberg is characterised by a
diversified economy with people employed in a range of sectors, the largest of which are
agriculture, trade, manufacturing, electricity/water, financial and services (Figure 3.2). The
financial and services sectors are the fastest growing sectors, largely due to the influx of
retirees and migrant labourers, and an increase in tourism.
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Figure 3.1: Employment in the Overberg DM is diversified (Overberg DM, 2002)
3.15 INTERESTED & AFFECTED PARTIES
The Department of Mineral Resources (DMR) has indicated that the minimum requirements for
public participation in terms of the Minerals and Petroleum Resources Development Act (Act. 28
of 2002) for exempted organs of state would include liaison with the landowner, notification of
the immediate neighbours and either an on-site advertisement or an advertisement in the local
newspaper.
The public consultation process for this project has involved consultation with the landowners
and neighbours, and the advertising of the proposed activities in the local newspaper.
Landowners were actively engaged; their concerns were noted, and these will be incorporated
into the final agreement reached. The PGWC has indicated a commitment to developing and
maintaining good relations with landowners.
We would contend that this should suffice to meet the legal requirements as the impacts
associated with the proposed activities are very localised (limited to within 1 km of the proposed
sites) and accordingly would be most directly experienced by the landowners.
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