Mt Keith has no outstanding environmental non-compliances from previous years. Two non-compliances were recorded in 2004. View 2004 environmental non-compliance incidents for MKO.

A Level 2 non-compliance involved the release of saline water from the tailings dam return water pond, after pumps failed to shutdown at the high water level. The saline water was released into a previously rehabilitated area and a stand of Mulga shrub-land. Approximately eight hectares of land was affected. Vegetation in this area has been closely monitored since the spill; however no over storey vegetation death was observed. To prevent a recurrence of the incident, level sensors were relocated and changes were made to the operating range of the pond. An extra interlock was also added to the system to stop pumps in the event of a high water level during manual operation. Alternative emergency overflow areas were investigated and this has been redirected to a contained area that will not affect vegetation.

A Level 1 non-compliance involved saline water leaking from an old repair on a buried pipe at the Albion Downs Borefield affecting 800m² of spinifex vegetation. It is not anticipated that vegetation in this area will be affected greatly due to the sandy nature of the soil and as heavy rain fell one day after the event. Corrective actions implemented to prevent a re-occurrence of this type of incident include new procedures for repairs to buried pipelines and a review of bore field componentry lifecycles for incorporation into maintenance schedules. This non-compliance is still outstanding for 2004, having occurred two days before year-end.

In 2004, revised environmental compliance checklists were developed for all departments on site. These have been developed to encourage better understanding and responsibility for compliance with site environmental operating conditions.

Resource Use

Annual environmental targets established for total water use, high quality water use, energy use, land rehabilitation earthworks and land revegetation were all met. High levels of rainfall during the year and increased harvesting of water through the central discharge tailings facility led to total water use being significantly below the target level.

Water usage includes groundwater extracted from nearby aquifers for use at the mine and processing plant as well as the Mt Keith Village and water from mine dewatering used in the processing plant. High quality water is defined as water containing less than 5,000mg/litre total dissolved solids. Groundwater extracted from the Albion Downs borefield contains approximately 60,000mg/litre total dissolved solids while groundwater extracted as a result of dewatering activities contains 10,000mg/litre total dissolved solids.

Effective management of the tailings storage facility is essential to ensure maximum recovery of water from the tailings dam to the process plant. In 2004 an average of 35% of water in the tailings was returned to process operations.

Land Management and Biodiversity

The natural environment around MKO includes a diverse group of ecosystems such as breakaways, mulga woodlands, shrub-lands and spinifex grasslands. Environmental education on-site plays a key role in raising awareness and shaping attitudes and behaviour regarding environmental sustainability.

The mine leases associated with the MKO cover approximately 104,800 hectares, and total disturbance to date associated with the mine, the minerals processing and infrastructure is 3,800ha.

Fauna

MKO contributes funding to an ongoing fauna monitoring study by CALM (WA Conservation and Land Management Department). The monitoring is focused on mammals within the Mt Keith area, in particular the rare and endangered Mulgara. Monitoring trials have been conducted since 2000. The study aims to identify why the numbers of Mulgaras fluctuate from year to year, (see Mulgara Case study).

Priority Flora Species

MKO has identified seven priority species of plants on the mine leases. Populations have been identified, counted and recorded and, in areas of high activity, the plants are flagged to avoid disturbance. Photographic cards detailing priority species are distributed to people working in areas where disturbances may occur.

Weed Control

An annual weed control program continues to be implemented at MKO. Weeds impede rehabilitation success and therefore all rehabilitated areas are regularly checked. In 2004, weed control was also carried out around the mine and Mt Keith Village. This included aerial spraying on the slopes of the mining pit to prevent spread of seed.

Feral Animal Control

Feral cat trapping was conducted regularly during 2004 and was supplemented by a two week trapping program, in conjunction with CALM, extending from around the mine out to Wanjarri Nature Reserve. More than 40 cats were trapped in 2004. It is expected that feral cat trapping will be an ongoing program.

In the first half of 2004 an increase in the rabbit population was visually identified. However the population decreased dramatically in late 2004 due to spread of the myxomatosis and calici viruses into the area. To control the remnant rabbit population a program of trapping and poisoning will commence in 2005.

Borefield Pipeline Upgrade and Leak Detection

Saline groundwater extracted from the Albion Downs Borefield is transported to MKO via pipeline. Failure of the pipeline can result in the release of saline water that can cause vegetation stress or death of native vegetation.

To minimise the potential impact of pipeline failures an upgrade of our leakage detection system was undertaken in 2004. This involved the installation of new flow meters and communication equipment that has improved the reliability and speed of response of the saline water leak detection system.

Rehabilitation

Disposal of tailings is an integral part of our operations. MKO has produced tailings since our operations commenced in 1994, initially depositing them into two small interim facilities. In 1996, a larger centralised tailings storage facility was commissioned.

Effectively revegetating the tailings surface can be difficult due to the saline nature of the material and the movement of this salt into growing mediums. Trials began in 2000 to find the optimum method of covering the tailings before replacing the topsoil. The trials involved comparisons of different cover materials and different depths of these cover materials.

Monitoring has been undertaken to assess the salinity uptake into the cover material. The hard pit rock capillary break layer in the larger cover performed best with upward migration of salts largely prevented. However, this also resulted in the least vegetation establishment due to the lack of water holding capacity. For all cover materials trialled salinity levels were much higher in the small cover elements than in the large cover. The salt uptake result indicates that highly salt-tolerant species (salt-bush) for revegetation need to be trialled, and rabbits effectively excluded to give emergent vegetation every chance of survival. Further rehabilitation trials on the tailing storage facility with salt tolerant species are planned for 2005.

The design, operation and progressive rehabilitation of waste rock dumps is also a critical part of our operations. The inner slopes of the MKO waste rock dumps were rehabilitated progressively between 1996 and 2002. Topsoil stockpiles are also rehabilitated to encourage re-vegetation which assists in maintaining biological activity within the soil and also reduces dust. Gravel pits that are no longer required have been rehabilitated. No waste rock dumps were rehabilitated in 2004 due to the expanding growth of the outer edges of the dumps. Areas where the waste rock dump has reached final edge limits will be rehabilitated in late-2005.

Annual monitoring of rehabilitated areas is undertaken to measure the success of rehabilitation. In 2004, the program was modified with the adoption of an Ecosystem Function Analysis approach. Using this technique previously rehabilitated sites will be compared to control sites to assess soil condition and vegetation performance.

MKO hosted a mine closure risk assessment workshop in 2004 with the Western Australian Department of Environment and Department of Industry and Resources. The objectives of the workshop were to engage key stakeholders and to conduct a risk assessment on the post-closure impacts associated with the tailings storage facility, waste dumps and contaminated sites. An action list was developed and this is being included in the revision of the mine closure plan.

Air Emissions

The majority of emissions at the MKO are derived from haul trucks emitting carbon dioxide and sulphur dioxide from diesel fuel combustion. Since 2003 we have been using an ultra low sulphur diesel for all our operations at MKO. This is estimated to have decreased sulphur dioxide emissions by approximately 90%.

Mining, transporting crushing and storing ore can create dust emissions. These dust emissions are normally controlled using a range of methods such as water sprays, dust scrubbers or enclosing known dust points.

Waste Management

MKO operates an extensive waste management program that includes the mine site, village and surrounding exploration activities. Waste is separated on site into recyclable and non-recyclable materials. Non-recyclable items are disposed of in the landfill area. Recyclable items including aluminium cans, paper, cardboard, plastic, glass, batteries and scrap metal are sent off site. In 2004 an estimated 97 tonnes of domestic recyclable material was removed from MKO. Improved management of waste has resulted in a reduction of waste going to the landfill and better use of our resources. Money received from recycling material is donated to local charities.

Other initiatives include regular site clean-up days and building awareness of waste disposal for shutdown crews.

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