Central Land Council

Rose Report One

Mining

Mining activities affect Aboriginal land in a number of ways. The most significant environmental effects of mining are localised to several sites where mineral and petroleum extraction is taking place. However, exploration activities can also have significant environmental impacts.

At present mining exploration interests held as exploration licences and applications for exploration licences cover over one third (123,000 sq km.) of all Aboriginal Freehold land in the CLC region (see Map 2). Map 2 Mining exploration interests in relation to Aboriginal land

Introduction

Mining activities began in the Territory in the 1870's, mainly for gold, with small scale production of tin, copper, silver and wolfram. In the late nineteenth and early twentieth centuries mining legislation gave persons holding a miners right unrestricted access to prospect on all Crown land. In 1918, however, the Aboriginals Ordinance was passed specifically excluding the holders of miners rights from Aboriginal reserves, and the subsequent Mining Ordinance passed in 1939 prevented the granting of mining leases on Aboriginal reserves.

Following the change in government policy from protection to assimilation in 1951, legislation was passed in 1952 and 1953 which permitted mining on Aboriginal reserves. This legislation also contained provisions for the payment of statutory royalties exacted from mineral production on Aboriginal reserves into an Aboriginal Benefits Trust Fund (ABTF). With the passage of the Aboriginal Land Rights (NT) Act in 1976 Aboriginal people regained the right of veto over mining activities on their land, and the ABTF was replaced by the Aboriginal Benefits Trust Account (ABTA) which acts as the main distributing institution for statutory royalties.

A consortium headed by Australian Gas and Light is extracting oil and gas from the Mereenie and Palm Valley areas approximately 150 km to the west of Alice Springs. Tanami Joint Venture has a gold mining operation on the Tanami road approximately 800 km from Alice Springs, and North Flinders Mines is extracting gold at the Granites and Dead Bullock Soak. In addition to the mining agreements above there are 39 exploration licence agreements granted over Aboriginal land. Another 2 agreements have been consented to by traditional owners and the Land Council and these are pending grant by the Department of Mines and Energy (DME).

There are another 147 applications for exploration licences which are currently in the process of being negotiated. Environmental impacts of mining The impacts of mining and exploration activities on Aboriginal land can best be examined by looking at the different stages of extraction of minerals and petroleum products.

Exploration

The initial stages of an exploration program usually consist of broad scale surveys based on remotely sensed data. Areas which are seen to present possibilities are often then overflown by aeroplane equipped with electromagnetic sensors designed to detect anomalies, enabling further targeting of on ground activities.

The sites of interest are then accessed by vehicle and preliminary soil sampling and measurements are made for later analysis. Up until this stage environmental effects are minimal and confined to vehicle tracks and isolated disturbance from sampling. In sensitive areas and isolated sites the use of vehicles can be minimised by using helicopters for access. Exploratory drilling and sampling Where initial indications warrant further exploration, prospective sites are usually drilled to sample over a range of depths. Drilling can be based on a grid pattern to enable the extent of the deposit to be determined. The environmental disturbance during this phase is greater due to the need to access drill sites with large machinery.

Access tracks to the sample grid are made and, therefore, they must be situated carefully to avoid subsequent erosion problems. The tracks over the grid area, and the need to manoeuvre large vehicles into the site, usually results in some disturbance to vegetation and soils. Mining Where mining activities proceed environmental impacts can be severe on a local scale, and there are some off-site environmental effects of note. The mineral deposits at the Tanami and Granites mines are being extracted from open cut mines.

The ore bearing minerals are then chemically treated to collect the target element, gold in this case. Where mineralisation is too deep for open cut mining underground extraction is used. The considerable amount of non-mineral bearing ore which is removed from the mine is stockpiled in waste dumps. Waste water and chemicals from the ore processing is stored in a tailings dam. In the extraction of petroleum products the impact of mining activities on the immediate environment is less severe as there is less need for disturbance to extract the target species.

The construction of pipelines for the transport of gas and oil are added impacts which result in some environmental effects extending from the actual site of extraction. (see 5.2.5). Roads and tracks The impact of vehicle access to remote areas in the arid zone can be significant. The tracks of a single vehicle over spinifex and shrubs on sandy country and around salt pans can remain visible for decades. While this is an obvious negative impact aesthetically it is not likely to result in any more tangible environmental problems.

Where tracks are more heavily used there is a significant likelihood that further complications may arise where tracks are situated in fragile or erosion prone areas. For example a track crossing a water course can precipitate a substantial erosion problem during infrequent but inevitable flood conditions. Similarly tracks on inclines and across vulnerable soil types can lead to channelling of run off waters and to gullying. The development of tracks is often seen by local Aboriginal people as a benefit because they can be used to access areas for hunting and subsistence activities and allow them to visit more remote areas of their land more easily.

This increase in local traffic can exacerbate other environmental problems which arise from increased access. Continued use is unlikely to allow the track to revegetate naturally and will most likely result in a permanent road depending on its utility for access to surrounding areas.

Pipelines

The type of pipeline construction is important in determining environmental effects. From an economic point of view underground pipeline construction is more expensive than above ground construction. Both below and above ground construction requires the clearing of woody vegetation from an easement of approximately 30 metres, however, both the aesthetic and environmental impacts of below ground pipelines are less than for above ground pipelines.

The main drawbacks of above ground pipelines are their high visibility and possible obstruction to the movement of wildlife and domestic and feral animals. The environmental impacts of below ground pipeline construction result directly from soil disturbance or loss of vegetation and habitat. During the construction phase the trench can act as a pit trap catching local animals species. The movement of people and vehicles can promote the spread of undesirable plant species along the pipeline easement and the soil and vegetation disturbance associated with construction can assist the establishment of these species.

Mineral extraction and processing

Mining at the Tanami and Granites mines is by open cut.

The economics of these operations is such that unless an open cut is mined out very quickly compared to the processing time, or an operation consists of many small pits, it is usually not viable to replace waste material in the open cut. This is particularly true of operations which have been going for a number of years. Where processing of the mined material occurs at the mine site the environmental disturbance can be much greater than that caused by the extraction alone.

As well as the actual processing buildings and infrastructure there is a considerable amount of waste material generated by the processing procedure. Waste material is usually disposed of on the surface in dumps, and liquid wastes are held in tailings dams constructed from solid waste materials. In central Australia the generally low relief around many mining operations increases the visual impact of mining operations and the changes to the landscape. The aesthetic impact of dumps and tailings dams is most keenly felt by those who live in the area.

Recent refusals by the traditional owners of the country on which the Tanami mine is located to allow the height of the dumps around the mine to be increased from 15 to 30 metres suggests that the impact of these features is a concern for local people. The need to limit dump height will result in a larger area of land being covered by dumps and a consequent increase in the efforts required to rehabilitate these areas following the cessation of mining activities.

Tailings dams are a possible source of environmental contamination as they contain solutions which are toxic, and for which safe storage must be maintained. The possibility of tailings contaminating ground water must be avoided as this water is vital for many remote Aboriginal communities. Fleming notes that all drainage systems in central Australia are internal, draining into the floodout areas in the deserts and salt-lakes. Any contamination will therefore remain in the region. The leachates and erosion products from waste dumps and tailings dams should be able to be confined to restricted areas in the short term. In the long term there is the possibility that they could gradually be dispersed into the drainage system during periods of above average rainfall or flash floods.

Rehabilitation

The Department of Mines and Energy (DME) have produced a code of conduct for environmentally sensitive areas which is a supplement to the more general code of conduct for mineral explorers in the NT. For individual mining operations the DME may also set specific conditions for the conduct of mining operations on grant of an exploration licence. When a mining title is granted the environmental requirements of the developer are covered by conditions attached to the title. Increasingly the industry is recognising the need to incorporate environmental rehabilitation programs into its operations.

This has come about because of increasing pressure on mining companies from public and conservation groups to be accountable for the environmental consequences of their actions. The extent to which mining rehabilitation activities can and will be successful in central Australia is yet to be determined. From an environmental perspective the development of roads in an environment which has hitherto been unaffected by European land management practices is generally seen to be negative. However, where these roads facilitate the expansion of traditional land management activities such as patch burning into remote areas some positive aspects of this development may result, provided road development is sensitive to environmental and cultural aspects of the landscape. Careful planning of these roads and tracks is therefore very important as they are likely to become well established through the continued use by Aboriginal landowners.

Summary

The discussion of mining has been limited to environmental impacts. Clearly their are a number of social and cultural impacts of mining and related activities on Aboriginal people. It is important that Aboriginal people and their support organisations remain aware of these issues. The impact of mining activities on the environment is localised and usually of a limited duration. The long term impact of mining activities will be dependant on the efforts made by the mining industry to rehabilitate the land following the extraction process. The expanding network of roads and tracks constructed for mining exploration activities on Aboriginal land will most likely remain, as natural revegetation can be a slow process in arid environments and any continued use of roads by local people will further hinder the process. As previously mentioned the development of these roads is seen as beneficial by local people because they provide access to more remote areas of their country allowing increased access for hunting and subsistence activities. However, from and environmental perspective this increased access also has the potential to lead to environmental degradation.