Port Hedland

Port Hedland

The Port Hedland operation is Dampier Salt's most recent acquisition, purchased in 2001, and covers just over 9000 hectares of operational area.

The production process at Port Hedland begins with seawater from the Indian Ocean. Powerful pumps with a total capacity of 1640 cubic metres per minute transfer the seawater into a nine-pond concentration system. Salinity is increased through each step of the system, which spans 7,800 hectares. Gravity causes the seawater to flow through the initial concentration ponds after which transfer pumps life the brine to flow into the final concentration pond. The saturation of the original seawater has increased from 17 to 90 per cent.

Axial flow pumps elevate brine from the concentration system along a specially designed 21 kilometre ditch system, which flows into a Pickle Pond. The solution is held in the Pickle Pond until it reaches full saturation and becomes feed stock for the crystallisers. The crystalliser system consists of 30 crystallisers with a combined area of 1,126 hectares. Saturated brine is pumped from the Pickle Pond via an open ditch to the crystallisers. Each crystalliser is filled with feed brine to a depth of 50 centimetres. The crystallisers are sampled each week to determine salt growth and the quality of brine. Careful forward planning ensures that adequate salt reserves are available for harvesting to meet the shipping requirements of the customers. When the salt has grown to a thickness of 25 to 40 centimetres, the residual brine is drained off in preparation for harvesting.

Harvesting begins with the ripping of the salt, which has been grown on a salt pavement. The combination of salt and floor support the large trucks and equipment used in the harvesting process. The harvesting capacity is 1,800 wet tonnes per hour. Once harvesting is complete, the salt floor of the pond is levelled in preparation for the next batch of salt. Fresh brine is introduced into the crystalliser and process starts again.

The salt is transported to the wash plant by 180 tonne, bottom dump trucks, discharged into the hoppers and conveyed to twin-screw washers. The salt is washed to remove insoluble materials and fed onto a static screen where brine and seawater sprays remove the residual liquor that surrounds the salt crystals.

The salt then flows onto a static screen where brine is removed. The salt washing process reduces a range of impurities including calcium, magnesium, sulphates and insoluble matter. The wash plant has a rated capacity of 1,500 tonnes per hour. The product salt is fed onto a radial stacker, which moves through an arc of 180 degrees to from a stockpile with storage capacity of over 750,000 tonnes.

The salt is left to drain for up to six weeks to reduce moisture and other impurities to meet the strict Dampier Salt quality standards. Once the salt has reached specification, it is transported by trucks, nine kilometres to the port stockpile area. The stockpiles are located near the Port Hedland deep-water berth.

The ship loader has a peak capacity of 3500 tonnes per hour and has the ability to load vessels of up to 75,000 DWT.

Process overview

Salt field data
Current production capability 3.2 million tonnes/ year
Average evaporation (fresh water) 3300 mm/year
Average shiploading rate 2500 - 3000 tonnes/hour
Length of levees and causeways 213km
Average evaporation of field 408,000 tonnes of water/day
Peak shiploading rate 3500 tonnes/hour
Average rainfall 290 mm/year
Salt deposited in crystallisers 260 mm/year
Berth depth at low water 13.5 metres
Total operational area 9,086 hectares
Peak evaporation of field 980,000 tonnes/day