Environmental Performance

The Kalgoorlie Nickel Smelter and Kambalda Concentrator recorded one Level 2 environmental non-compliance, and two Level 1 non-compliances for 2004. View 2004 environmental non-compliance incidents for KNSC.

The Level 2 environmental non-compliance occurred in June 2004 when approximately 50 kilolitres of water containing a very small quantity of nickel was spilt when water was being transferred between two storage dams at the Kalgoorlie Nickel Smelter. The water flowed over the spillway and onto land adjoining the project site.

Much of the water in the dams that overflowed was stormwater runoff, so potential impact on fauna, flora, soils and groundwater is expected to be very low. To prevent a reoccurrence of the incident, procedures governing the transfer of water between dams and the inspection of the dams have been updated. Investigations concluded that automated level indication and pump control was neither practical nor warranted.

The first Level 1 incident was the identification of a minor exceedence of the emission limit for particulates within gases discharged from the concentrating drying stack under test conditions. Investigation found that inadequate maintenance and incorrect operating of the scrubber resulted in the inefficient operation of the scrubber system and high particulate emissions. The problems were rectified and subsequent sampling results showed that the dryer emissions were well within licence limits.

The second Level 1 incident involved the use of saline water to suppress dust within the Mt Burges Sand mine, which is not permitted as part of the mine's Environmental Management Plan. The requirement to avoid using saline water was re-communicated to the contractor. The limited application of saline water is not expected to have any long-term impact on the rehabilitation of the sand mining pit.

As a result of the Level 2 non-compliance in November 2003, involving a tailings line failure and discharge of tailings onto an adjacent salt pan at the concentrator, a new steel/HDPE pipe was installed from the tailings thickener to both TSF2 and TSF3A. This replaced the asbestos cement pipeline and cost approximately $500,000. It is expected to substantially reduce the risk of future pipeline failures.

There were no outstanding environmental non-compliances at the end of 2003 or 2004, which is a pleasing result of the quick and effective management of KNSC's environmental obligations.

Resource Use

KNSC met all the annual environmental targets established for total water use, high quality water use, energy use, land rehabilitation earthworks, land rehabilitation, revegetation and sulphur dioxide recovery.

Land Management and Biodiversity

A vegetation-monitoring program was established in 1987 to monitor the effects of sulphur dioxide emissions from the Kalgoorlie Nickel Smelter on the surrounding native vegetation. The vegetation monitoring sites are located at various distances, ranging from 350m to 42km, and in various directions from the smelter stack. The vegetation-monitoring program has included annual assessments of non-vascular and vascular plant species. The non-vascular plant species include foliose lichen species. These lichen species are recognised internationally as being susceptible to gaseous emissions.

The monitoring program has assisted in determining the vulnerability of different species to seasonal rainfall conditions and identifying the effect on different species in relation to their location from the smelter. Overall the vegetation is persisting and maintaining its vigour in most areas. There has been a localised decline in the foliage of some species in close proximity (less than 1.5km) of the smelter. Since the commissioning of the acid plant in 1996, monitoring has identified a subsequent reduction in emission positive indicators. This includes the establishment of seedlings, which, for some species, has offset the earlier localised decline in plant condition.

During 2004, KNSC undertook a review of its baseline environmental data. The findings of this data will be used to review the frequency of future vegetation and fauna surveys. In particular, the findings will be used to determine the need for fauna surveys, which have not been undertaken at the smelter and concentrator since August 1996. KNSC will also undertake a review of the ongoing scope of vegetation monitoring.

Declared rare flora (Pityrodia Scabra) occurs within the Kambalda region, including on some leases owned by WMC that contain powerlines and substations. Some colonies also occur on leases divested by WMC as part of the Gold Business Unit sale and subsequent Nickel asset sales. The rare flora colonies are managed by signage in the area, education of contractors working in the vicinity of colonies and use of disturbance permits when clearing vegetation. KNSC's only potential for impact occurs during maintenance of the power line corridor (i.e. maintaining cleared areas under powerlines). To minimise impact, care is taken not to disturb colonies or individual plants during any maintenance activities.

Rehabilitation

While no major rehabilitation was completed during 2004, an important step was taken toward measuring the success of rehabilitation already completed on disturbed areas. This involved the use of Ecosystem Function Analysis (EFA), which was developed by the CSIRO to monitor the success of rehabilitation already undertaken. CSIRO site technical description of EFA.

Ecosystem Function Analysis transects have been established on the rehabilitated portion of the hot slag dump and old granulated slag dump at Kalgoorlie Nickel Smelter and within rehabilitated areas of Mt Burgess Sand Mine. Comparison sites were also selected in undisturbed bush surrounding Kalgoorlie Nickel Smelter to be used as a basis for comparing rehabilitation success.

The transects will be monitored each year for the first three years and then every second year. The results will be compared over time to assess rehabilitation success. The results will influence future rehabilitation techniques and provide evidence towards 'sign off' of rehabilitated areas by the regulatory agencies.

Kambalda Disused Tailings Cell

Closing and rehabilitating tailings storage facilities represents a significant challenge for KNSC's operations. Kambalda Nickel Concentrator's main tailings storage facility comprises three 'cells'. The oldest cell is on an island on the north-west edge of Lake Lefroy. Constructed in 1973, it reached capacity in 1989. Rehabilitation and, where possible, revegetation of the 22-hectare 30-metre high facility will be required.

During 2000, comprehensive geotechnical and geochemical investigations commenced, and instrumentation to monitor seepage was installed as part of developing a robust closure plan. The geotechnical investigations to date have included a review of the stability of the outer slopes that have an angle ranging between 21 and 41 degrees. These investigations demonstrated that if surface erosion were controlled, there would be no significant long-term geochemical, stability or seepage risks.

Since 2000, KNSC has run large-scale revegetation trials on the upper surface of the oldest tailings cell to address key erosion issues. It also built a full-height 150-metre-wide slope-cover trial section on the south face of a newer cell in 2001. Both trials are very encouraging, and will be used to develop a final closure strategy for the oldest cell. It is anticipated that the final closure strategy for the cell will be completed by the end of 2005.

Air Emissions

The smelter is located 12km south of Kalgoorlie, and therefore, management of sulphur dioxide emissions from the smelter is a significant environmental challenge. In 1996 the commissioning of a $170 million sulphuric acid plant reduced sulphur dioxide (SO₂) emissions by over 90 per cent. This was a major contribution to improving air quality in the Kalgoorlie region.

In March 2003, the Environment Protection (Goldfields Residential Areas) (Sulfur Dioxide) Policy was revised, reducing the sulphur dioxide limit to 0.25 parts per million (ppm) by 2005. To ensure KNSC meets these requirements the smelter has continued to operate under the comprehensive Air Quality Control System. This consists of a sulphur dioxide-monitoring network to ensure emissions do not impact adversely on the community or regional environment. This consists of ten ambient SO₂ monitoring stations in Kalgoorlie-Boulder, Coolgardie, Kurrawang and Kambalda, operated in conjunction with Kalgoorlie Consolidated Gold Mines, Kanowa Belle Gold Mines and two meteorological monitoring stations. Real time weather data and SO₂ data is then used to determine plant-operating strategies, which will ensure protection of Environment Protection Policy areas.

An upgrade of the Air Quality Control System was completed during 2003/2004 and was commissioned in April 2004. The upgrade utilises the latest technology and ensures the ongoing reliability of the system. The system is now fully integrated into the existing process control system, and anyone on-site can view the information via the computer network. WMC personnel can also interrogate the system remotely. The capital cost of the new system was $459,000 and ongoing operating costs are approximately $100,000 per annum.

Total SO₂ emissions to atmosphere during 2004 were 36,681 tonnes. The main sources of emissions are stack emissions from the converters (34,700 tonnes) and the acid plant (1,216 tonnes). The remaining source of SO₂ emissions is fuel combustion.

NOx emissions can occur from the acid plant stack and main furnace stack. NOx emissions in the acid plant stack are minimised by implementing strict operating parameters, which ensure excess volumes of air are not introduced into the acid plant converter beds. To further reduce the risk of this occurring, engineering controls are being investigated. NOx emissions within gases emitted from the main stack are a by-product of fuel combustion processes within the furnace and converters.

Waste Management

During 2004 work continued in three keys areas of waste management: weak acid residue from the acid plant, management of waste water and storage of Kwinana Nickel Refinery residue.

Weak acid is currently treated using hydrated lime. In 1999 plant modification was undertaken to separate the residue into two streams: an uncontaminated clean gypsum stream and a metal-contaminated gypsum stream. Co-disposal of the uncontaminated gypsum was undertaken with the slag residue, produced as part of the smelting process. It is planned that weak acid will be transported to WMC's Mt Keith operation from Q1, 2005. The metals within the weak acid will be stabilized through the injection of the weak acid into either the process or tailings stream.

Waste water at the smelter consists of stormwater run off and process water streams, including cooling tower water bleeds. Historically this water has been used in the slag granulation process, resulting in loss of the water through evaporation. The use of the slag granulation process is no longer required as a core part of the process. Alternative methods of reusing or treating the water have been investigated, which identified the potential to transfer the water to Kalgoorlie Consolidated Gold Mines for use in the gold processing operation. Consequently the water is now pumped into Kalgoorlie Consolidated Gold Mines existing borefield line, which passes to the west of the smelter. A total volume of approximately 110,000 m3 per annum is expected to be transferred during 2004. The transfer of water to Kalgoorlie Consolidated Gold Mines helps the smelter manage its waste water, ensures zero discharge of water to the environment and reduces Kalgoorlie Consolidated Gold Mines groundwater usage.

Residue from Kwinana Nickel Refinery contains valuable concentrations of metals, but, historically, a cost-effective recovery option was not available. As a result the residue was stored at Kambalda Nickel Concentrator between 1986 and 2002 (some deliveries are still received if the weather conditions prohibit road transport elsewhere). The material was stored on top of an old tailings storage facility and controls were put in place to minimise dust emission. In 2002 an agreement was reached with Minara Resources regarding the purchase of the residue for processing at its operations at Murrin Murrin. At present 5,000-7,000 tonnes of residue is removed from Kambalda Nickel Concentrator each month and taken to Minara Resources operations. At current rates, the remaining stockpile of material will be removed by the end of 2005, allowing the area to be rehabilitated.

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