Burnside Gold Project

Environmental Assessment Report and Recommendations

Burnside Project Northern Gold NL
by
M.J.Nolen
Senior Environmental Officer
Environmental Assessment and Policy
Department of Mines and Energy
April 1997

Contents

1.0

Introduction

2.0

The Proposal

3.0

Major Issues

4.0

Environmental Assessment

4.1

Waste Rock Management

4.2

Water Management

4.3

Flora/Fauna

4.4

Rehabilitation

4.5

Heritage

4.6

Environmental Monitoring

5.0

Conclusion

Appendices

Synopsis of Advisory Board Comments

1.0 Introduction

The Burnside Public Environmental Report (PER) has been assessed in accordance with provisions of the Environmental Assessment Act and administrative arrangements between the Department of Lands, Planning and Environment and the Department of Mines and Energy.

The proposed Burnside project is a relatively short termed operation (3.2 years) of a medium scale and is considered to have a limited potential to cause any significant long termed environmental impact, if appropriately monitored and managed.

This report assesses the possible environmental impacts of a proposal by Northern Gold NL (NGNL). NGNL propose to establish three open cut pits and an associated haul road 12 to 23 km north of their Burnside mine site (formerly Cosmo Howley). The Burnside mine site is located approximately 45 km south-east of Adelaide River, Northern Territory.

The review process of the PER included comments by the following advisory bodies:

Aboriginal Areas Protection Authority
Department of Mines and Energy
Department of Lands, Planning and Environment
Department of Primary Industries and Fisheries
Department of Transport and Works
Northern Territory Attorney-General’s Department
Parks and Wildlife Commission of the Northern
Territory
Power and Water Authority
Museum and Art Gallery of the Northern Territory
Territory Health Services
Work Health Authority

A synopsis of the comments is provided in Appendix A.

Included in this report is a discussion of the main issues associated with the proposal, the potential impacts of the proposal on the environment and recommendations on how the identified impacts should be managed.

The contents of this report form the basis of advice to the Northern Territory Minister for Lands Planning and Environment in accordance with provisions of the Environmental Assessment Act and administrative arrangements between the Department of Lands Planning and Environment and the Department of Mines and Energy.

Assessment of the PER has identified a number of aspects that require additional attention by NGNL. These issues are best addressed through reviewable Mine and Environmental Management Plans that require formal approval by the Department of Mines and Energy.

It is recommended that no further assessment of this proposal is required under the Environmental Assessment Act.

Recommendation 1

NGNL shall ensure that the proposal is implemented in accordance with the environmental commitments and safeguards identified in the Burnside Project Public Environmental Report, or as modified in this assessment report, or an approved Environmental Management Plan.

2.0 The Proposal

Northern Gold NL has acquired mining leases covering the Burnside mine site (formerly Cosmo Howley) and existing mines at Chinese Howley and Big Howley, located approximately 45 kilometres south-east of Adelaide River, Northern Territory.

NGNL proposes to develop three new deposits at Kazi, Western Arm and Bridge Creek 12 to 23 kilometres north of Burnside. NGNL will mine 1.24 million cubic metres of ore by open cut method from the three sites and transport it by road train, via a dedicated haul road with an underpass under the Stuart Highway, to Burnside for processing at the existing facilities. The tailings produced in processing will be discharged to the existing Cosmo Howley Pit, which has been used for this purpose for some years by the previous mine operators (Dominion Gold).

It is estimated that approximately 7 million cubic metres of waste rock will be produced from the three mines and this would be placed into above ground dumps located adjacent to each of the pits.

The three deposits are intended to supplement ore sourced from the Howley mines to maintain viability of the Burnside processing operation for several years. Mining of the three deposits is currently planned to take approximately 3 years recovering 1.2 million cubic metres of ore.

3.0 Major Issues

The major issues associated with the Burnside project, specifically the three mining operations and associated haul road, are listed below.

Waste rock/acid mine drainage management
Water management
Rehabilitation

4.0 Environmental Assessment

4.1 Waste Rock Management

The primary potential impact of this proposal is for the formation of acid mine drainage (AMD). The waste rock characterisation outlined in the PER was considered adequate to provide an indication of the potential of the various lithology's to produce acid. NGNL has outlined extensive test and mitigation measures in the PER to monitor and prevent the formation of AMD.

Encapsulation of acid producing materials through appropriate engineering design and construction of the waste dumps is a key factor in the prevention of acid production. An ongoing geochemical test work program will be implemented during mining of all three deposits to quantify the exact location and volume of potentially acid producing waste. This program will be used to plan appropriate waste disposal locations within the waste dumps and to modify disposal strategies as appropriate.

Recommendation 2

NGNL should prepare a waste rock management plan to include:

waste rock dump site preparation; methods of waste rock characterisation; selective handling of material; waste dump construction design; and
a monitoring system for:
- checking on waste rock placement compaction, and
- potential acid production.

4.2 Water Management

Concerns relating to the mine water management system focus on containment of potentially contaminated water from the mining and waste dump runoff and the potential effects on groundwater through the disposal of tailings to the Cosmo Mine pit.

The prime objective is that contaminated surface waters, containing either chemical or physical pollutants, are contained and that any offsite discharge be licensed and controlled.

A review of monitoring procedures for the tailing disposal site, including the location of new groundwater monitoring bores, will be required prior to the commencement of milling.

The PER indicates that potentially contaminated water from the mining and waste dumps will be managed by the use of wetlands and irrigation to the surrounding country side. Properly constructed wetlands and managed irrigation schedules have been shown to assist in the management of mine waters.

Designs, schedules and monitoring proposals for the proposed water management systems will be required prior to the commencement of the project. NGNL will also require the necessary licences for any discharge from the mining lease.

Recommendation 3

NGNL should prepare a water management plan which includes:

wetlands design criteria; irrigation design criteria; characterisation of discharge waters; a groundwater monitoring strategy; and
monitoring of water quality/quantity prior to release/disposal.

This water management plan should be incorporated into the Environmental Management Plan and reviewed on a routine basis by the Department of Mines and Energy.

4.3 Flora/Fauna

It is important that impacts be minimised on the existing biotic environment and that the existence of endangered/threatened species is addressed prior to the destruction/modification of the immediate habitat.

Concerns relating to the fauna survey methodology focus on the limited nature and duration of the surveys. The prime concern is that the surveys were limited to the actual pit areas and did not encompass the waste dumps, areas adjacent to or surrounding the entire operations.

Displacement of fauna will not be limited to the pit areas. Due to habitat disturbance/removal an area several times the actual area of the pits will be impacted upon.

Also, the PER did not contain a list of the identified flora for the proposed sites. As a result it is not possible to determine the existing status of weeds at the proposed sites therefor there is no base line for ongoing monitoring. It is also not possible to view the species composition/richness again for monitoring and rehabilitation.

Recommendation 4

NGNL should carry out additional flora and fauna surveys to reliably determine the fauna and weed species in the area and to ascertain whether any threatened species are likely to be affected by the project. This will also enable 'bench-marking' for future surveys and monitoring.

In line with the Northern Territory Weed Management Strategy, 1996 - 2005, NGNL should design a weed management plan to prevent the introduction and spread of weeds.

This information should be incorporated into the Environmental Management Plan and reviewed on a routine basis by the Department of Mines and Energy.

4.4 Rehabilitation

The rehabilitation strategy proposed in the PER is considered adequate at this time. During the development and operation of the mine, a detailed rehabilitation plan will be developed through rehabilitation trials and on-site experience.

Due to the multi-pit nature of the project, it is intended that rehabilitation techniques applied to disturbed areas associated with one pit will be reviewed and altered, as required, according to rehabilitation success. Any improved techniques subsequently identified would be applied to the programs at remaining areas to be rehabilitated.

Effectiveness of rehabilitation trials will be assessed in annual reviews and utilised to improve management practices and formulate a final rehabilitation plan for the sites.

Recommendation 5

Rehabilitation trials should be undertaken to develop a final rehabilitation strategy.

This information should be incorporated into the Environmental Management Plan and reviewed on a routine basis by the Department of Mines and Energy.

4.5 Heritage

A number of archaeological sites were identified in or near the proposed mines and haul road. The proposed mining operations have the potential to impact on a number of these site either directly (destroying) or indirectly (disturbing).

The Heritage Conservation Branch of the Department of Lands, Planning and Environment have outlined a number of points which may require discussion and actioning by NGNL prior to the commencement of the project.

Recommendation 6

NGNL should liaise with the Heritage Conservation Branch of the Department of Lands, Planning and Environment to establish specific requirements for each of the identified archaeological sites.

This information should be incorporated into the Environmental Management Plan.

4.6 Environmental Monitoring

NGNL has outlined in the PER a proposed sampling and monitoring program. All components of the monitoring program will be implemented at the commencement of operations. Baseline surface water quality and groundwater level monitoring will be completed before the commencement of operations.

NGNL propose to develop their sampling and monitoring program prior to commencement of operations and will provide the details in their first EMP.

Recommendation 7

NGNL shall submit a complete baseline and operational monitoring programme, including identified parameters and thresholds in an Environmental Management Plan.

NGNL should operate in accordance with the approved plans, with these plans being reviewed by the Department on a regular basis.

5.0 Conclusion

Assessment of the PER has identified some issues which will require attention/clarification by Northern Gold NL. These issues can be adequately addressed through existing regulatory and administrative processes such as the reviewable Environmental Management Plan.

As a result of this assessment the Department of Mines and Energy will require NGNL to prepare an Environmental Management Plan (EMP) for the approval of the Secretary. The EMP will address the 'Commitments' made by NGNL in the PER and all environmental issues identified as relevant to the Burnside Project.

These issues include:

Waste rock management;
Water management;
Rehabilitation;
Heritage sites management;
Mosquitoes and biting insects control;
Environmental monitoring programs; and
Environmental Management Plan amendments.

Through the assessment of monitoring results the EMP, or parts thereof, will be reviewed on a regular basis to assess the performance of management practices. Adverse trends can be detected before developing into environmental problems and can be dealt with through appropriate modification to management practices. The EMP becomes a practical management tool that can be utilised for environmental audit purposes.

Recommendation 8

NGNL should prepare and submit Mine and Environmental Management Plans to the Department of Mines and Energy for approval.