Summary
The Hong Kong registered motor bulk carrier Mineral Diamond of 141028 tonnes summer deadweight, sailed from the Western Australian port of Dampier on 11 April 1991 for the Netherlands port of Ijmuiden, by the way of the Cape of Good Hope. On sailing the vessel filed a voyage plan and indicated that it would participate in the Australian Ship Reporting System (AUSREP).
Six routine AUSREP messages were received by the Marine Rescue Co-ordination Centre, Australia (MRCCAUS), from the Mineral Diamond. The last of these messages at 0600 UTC (1400 Western Australian Standard Time) on 17 April reported that the vessel had reduced speed to six knots in force 9 to 10 winds (45 to 50 knots) in six metre seas, in position 30 degrees 21 minutes South 087 degrees 48 minutes East. When the Mineral Diamond failed to send her next scheduled message officers of the MRCCAUS initiated routine procedures to establish the safety of the ship and crew. When routine procedures failed to establish the ship's safety an air search was launched early on 20 April, coordinated by MRCCAUS and conducted by the Royal Australian Air Force, centred on a position 1500 miles west of Perth. When no trace of either ship or survivors was found the search was abandoned on the evening of 24 April.
It is assumed that the Mineral Diamond foundered with the loss of all hands in a position some 1500 miles to the west of Perth.
The Australian Marine Investigation Unit, in accordance with the International maritime Organization Resolution A440 (XI) "Exchange of Information for Investigations into Marine Casualties" and under the provisions of the Navigation (Marine Casualty) Regulations, undertook an investigation of the evidence that was available within Australia to assist the Hong Kong Authorities.
Conclusions
The re-analysis of the surface pressure field indicates that the strongest surface winds would have been experienced in the 12-hour period from about 0000 UTC 17 April 1991. Satellite pictures indicate a northward surge of cold air and the development of a new front in the vicinity of "Mineral Diamond" at about 1200 UTC leading to very squally conditions. The estimated 10-minute mean winds are in the order of 50 knots. Accordingly, significant waves to about 9 metres can be expected to have developed at this time in the vicinity of "Mineral Diamond" with a maximum wave to around 18 metres. Although the winds then eased, significant waves to 7 metres would have persisted through 18 April with a maximum wave up to 14 metres.