Brockman 4

Overview

The Brockman 4 iron ore mine is located in Western Australia. It is an open pit operation with site-based processing facilities. The mine commenced operation in 2010.

Rio Tinto iron ore operations in the Pilbara have an annual capacity of 220 million tonnes, with advanced plans to increase capacity to 283 million tonnes by 2013, on a pathway to 333 million tonnes. With a network of 14 mines, three shipping terminals and the largest privately owned heavy freight rail network in Australia, Rio Tinto's Pilbara operations make up a major part of Rio Tinto's iron ore activities globally. Rio Tinto's operations began in 1966 and are well positioned to meet the growing needs of the world's iron and steel industry.

In the Pilbara, Rio Tinto wholly own Hamersley Iron's eight mines and also operate the Hope Downs mine (50:50 joint venture between Rio Tinto and Hancock Prospecting Pty Limited), the Channar mine (Rio Tinto: 60 per cent) and the Eastern Range mine (Rio Tinto: 54 per cent). Rio Tinto's iron ore operations in the Pilbara also include a 53 per cent interest in Robe River Iron Associates' three mines: Mesa J, Mesa A/Warramboo and West Angelas.

The Brockman iron ore is shipped to the port of Dampier.

Location

The Brockman 4 iron ore mine is located 60 kilometres north-west of Tom Price, West Australia.

Western Australia occupies the whole western part of the continent. Its economy is largely driven by extraction and processing of a diverse
range  of mineral and petroleum commodities. The state contributes an estimated 58 percent of Australia's Mineral and Energy Exports.

Geology and Mineralization

The Pilbara region is located in the northwest of Western Australia, approximately 1,100km north of Perth. The region contains the 80,000 square km Hamersley Iron Province. The geology of the Province is characterized by a 2,500 million years old group of late Archaean and early Proterozoic rock formations known as the “Hamersley Group”.

The Hamersley Group was formed by chemical sedimentation of minerals in a marine (ocean) environment. The processes which formed the Hamersley Group occurred after volcanic activity introduced basalt rocks in the area. Sedimentary rocks like sandstones also occur in the group due to weathering and transportation of rocks which occurred during the period when the Hamersley Group was formed.

The Hamersley Group is approximately 2.5km thick. It contains several large units of Banded Iron Formation (BIF): rock with bands of iron minerals (magnetite and hematite) and gangue minerals (mostly carbonates, silicates and chert). Typically, unenriched BIF contains about 30 per cent iron by weight.

The BIF layers have been deformed by geological processes, and eroded by weathering resulting in the geological formations that we see today.

In the Pilbara, other types of ore deposit exist, notably channel iron deposits, but these are derived from the original bedded iron formations.

The Brockman Iron Deposits have four parts: the lower most Dales Gorge Member, the Whaleback Shale and Joffre Members, and the uppermost Yandicoogina Shale Member.  Brockman ore is mostly in the Dales Gorge and Joffre Members within the Brockman Iron Deposits.

Brockman Iron Deposits typically have hematite as the dominant iron mineral. Brockman deposits also have goethite in varying amounts and have varying phosphorus content and physical characteristics.

The variation exhibited by Brockman deposits is a result of different degrees of dehydration of goethite to microplaty haematite which also affects the amount of residual phosphorus content.

Brockman deposits range from blue grey in colour for deposits with the greatest degree of dehydration to grey-yellow-brown for deposit with higher amounts of goethite and less dehydration. 

Mining & Operation

Brockman 4 is an open pit operation with site-based processing facilities. The mine commenced operation in 2010.

Mining equipment consists of:

Haul trucks â€¢ 16 x Komatsu 830E-AC â€¢ 2 x Komatsu 730E

Load units â€¢ 3 x EX5500-6 Hitachi Shovel â€¢ 2 x Le Tourneau L1850 â€¢ 1 x EX3600-6 Hitachi Excavator

Auxiliary Equipment â€¢ 3 x 777F Cat Water Trucks â€¢ 1 x 980H Loader â€¢ 2 x 930H Loader â€¢ 4 x D11T Dozer â€¢ 2 x 854K Wheel Dozer â€¢ 2 x 16M Grader â€¢ 1 x Komatsu PC 300 â€¢ 1 x Cat 3900 Service Truck â€¢ 1 x Scania 6 Wheel Water Cart â€¢ 1 x Cat Haulmax 3900 Float

Drillsʉۢ 2 x Cubex QXR 1120ʉۢ 3 x Reedrill Drill SKSS-16

Production flow: Drill and Blast, Load and Haul, Process, Stockpile and rail-load out

Areas for open-pit mining are selected using the mine plan. Identified areas are tagged, and then holes are drilled in an appropriate pattern by rigs. The drill holes are filled with an explosive, most often ANFO (Ammonium Nitrate/Fuel Oil) and then charged. The resulting blast breaks the material to a size required for digging. 

Processing

Processing consists of crushing and screening.

The broken material is loaded for transport by face shovels, excavators or front-end loaders into haul trucks. Haul trucks at Rio Tinto Iron Ore operations are typically in the 190 tonne and 240 tonne class. Overland conveyors are used to transport partially crushed feed at sites where there are long distances between the pits and process plants Processing of the ore ranges from simple crushing and screening to a standard size, through to processes that beneficiate or upgrade the quality of the iron ore products. This is done by physical processes, which remove impurities by differences in particle density or size gravity or size separation. Processing may be wet or dry.

The processed ore is stockpiled and blended to meet product quality requirements, before being reclaimed and conveyed to rail load-out. The ore is loaded into ore for transport to the port facilities.

Ore is railed up to 460 kilometres to the coast along a dedicated privately owned rail system. A typical train consist comprises 2 GE Dash 9 locomotives, 230 ore cars and is over 2.4 kilometres long. A single driver, supported by centralised track control, operates the train.

The mine undergoes an expansion process that would see it doubling its current capacity of 22 million tonnes per year to 40 million tonnes per year by 2013.

Environment & Community

Rio Tinto's Iron Ore group seeks to balance economic, social and environmental considerations across all parts of its business. This is achieved by making sustainable development considerations an integral part of our business plans and decision-making processes. 

Rio Tinto's Sustainable Development and Climate Change Panel supports senior leadership to embed sustainable development into the way we work. The group oversees the organisation's identification and management of economic, environmental and social risks, and opportunities. 

In addition to Rio Tinto's statement of business practice, The way we work, Rio Tinto define its commitment to sustainable development with nine principles. Together, these principles guide the way we plan for the future.

Closure

The closure of a mine or other operating sites requires planning beyond simply rehabilitating the site. Rio Tinto consider the management of social issues resulting from closure, especially in remote areas where communities are dependent on the socio-economic benefits of the mine.

Rio Tinto plans for closure from the earliest stages of project development to decommissioning activities and are guided by the Rio Tinto Closure Standard. 

The intent of the standard is to ensure that Rio Tinto managed activities are left in a condition which minimises adverse impacts on the human and natural environment.

Rio Tinto experiences with closure planning have helped the business understand that the environmental and social legacy is possibly the most tangible indicator of an operations contribution to sustainable development in the areas where we operate. Consequently, we have adopted a multi-disciplinary approach to closure planning, requiring a wide range of technical and business disciplines. 

These activities allow Rio Tinto to influence the design, development, operation and closure of all managed operations to ensure post-closure outcomes that meet needs and expectations outside of the business.

Product stewardship

Product stewardship means understanding the life cycle of the metals and minerals we produce, including the safe production, use and disposal of metal and mineral products as the need for them continues in society.

Increasingly, producers have both individual and joint responsibility with other stakeholders to ensure that products are managed safely across their life cycles. Our product stewardship work allows us to improve our understanding of the health, safety and environmental implications of the use of our products. Rio Tinto's product stewardship strategy emphasises the importance of understanding threats and opportunities in the market, and the importance of engagement with key stakeholders including customers, suppliers, regulators and communities. 

Rio Tinto is in the process of implementing a formal material-stewardship programme, as well as completing life cycle assessments on key products. Material stewardship is a collective term for resource, process and product stewardship. It means better understanding and taking responsibility for our iron ore products, from their discovery and mining, production, use and management at end of life.