Koolan Island

Koolan Island is an island off the Kimberley coast of Western Australia in the Buccaneer Archipelago. It is about 1,900 km (1,181 miles) north of Perth, and about 130 km (81 mi) north of Derby. It holds deposits of high-grade iron ore.

The island is approximately 12 kilometres (7 mi) in length along an east–west axis and approximately 3 km (1.9 mi) at its widest point along a north–south axis. It encompasses an area of approximately 2,200 hectares (5,436 acres). The island is only 1 km (0.62 mi) offshore, with a smaller island, Round Island, between Koolan and the mainland. Composed of Precambrian quartzite sandstone, the island has a rugged dissected terrain with jointed gorge forming narrowly valley drainage channels. The ridges have thin stony sandy soils. The highest point of the island is at 168 m (551 feet).

BHP commenced open-pit mining operations on Koolan and neighbouring Cockatoo Island in the late 1940s and by 1963 had established substantial mining operations there. The Koolan Island mine closed in 1994 after BHP had extracted 68 million tonnes of high-grade haematite ore, averaging 67% iron.

At its peak, Koolan Island had a population of 950 people and had a school, police station, recreation facilities and shops. It had the world's then-longest golf course hole — an 860 yards par 7 number 6 which doubled as the island's air strip.

Major rehabilitation of the island was undertaken since the mine closure, with buildings and exotic vegetation removed. Extensive replanting of native species has been undertaken.

When BHP ceased mining operations on the island in 1993 they flooded the Main Pit to the ocean by blasting part of the hanging wall. This has meant that the pit has been filled with approximately 10 billion litres of sea water, with a significant marine eco-system forming within the bounds of the former working pit. Due to the dense nature of the marine fauna within the Main Pit, Mount Gibson Iron plan to utilise numerous substantial blasts within the water filled pit in order to extract all marine creatures before dewatering operations are commenced. A Seawall will then be built around the ocean side of the pit in order to keep the ocean out. The pit will subsequently be dewatered in order to allow the rich ore reserves to be mined once again.

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