“This is a world-class facility,” chief operating officer Tony Cunningham told the visitors before their tour.
The Timaru scours and its sister plant in Napier are owned by Cavalier Woolscourers, which in turn is 50% owned by Cavalier Corporation and 25% each by the Accident Compensation Corporation and Direct Capital.
Both plants are run as commission scours.
“We don’t own any fibre,” Cunningham said.
Each plant can process up to 1000 tonnes a week of greasy wool but will handle lots as small as one bale if that’s what the customer wants. At Timaru, about 800 bales a day come in at the peak with eight production staff per shift and the plant running 24/7. There are two lines – one that’s 2.4m-wide and the other a 3m line newly designed and installed in 2008.
Cavalier Woolscourers’ chief operating officer Tony Cunningham checks the output.
Foreign objects in incoming bales are a big concern and staff are incentivised for every rogue non-wool item they find in the greasy wool. Metal detectors help but not with clothing, which if it slips through can contaminate thousands of metres of yarn with fibres that won’t dye.
All greasy bales are opened and blended before scouring so that when the clean bales reach the mill “every bale is homogenous,” Cunningham said.
For short wools – including bellies, necks, slipe and fleece with faults – machining through short-wool processors for dirt removal is the first step. Then all wools, including those that didn’t need decotting, are opened and evenly blended together using high-tech computerised equipment.
A triple-drum opener takes out dirt, seeds and short fibres, releasing a regular feed of wool on to the main line into the scour itself where the wool goes through three wash bowls and three rinsing bowls at 65-70C.
From there it’s dried with hot air. Heat for the Timaru plant’s air and water comes from about 120t a week of coal, while Napier uses natural gas. Both are very efficient.
“We are the first woolscouring company in the world to achieve Environmental Choice for Woolscouring EC47-11 accreditation,” production co-ordinator Struan Hulme told the WONZ visitors.
The final step in the process is the scoured wool cleaner that Hulme says is “a bit like polishing a car after you’ve washed it”.
Throughout processing, lines are constantly monitored and checked to achieve the desired output. “We want bale one of clean wool coming off the line to be exactly the same as bale 48,” Hulme said.
Then, as the scoured wool passes through to the press room, regular samples are taken and analysed for moisture content, residual grease, and colour. Anything out of spec goes back to the start and is rescoured while what goes through for pressing is traceable so that in the unlikely event a customer has a problem with a clean bale its analysis on exiting the scour can be checked.
Pressing is a two-stage process, ramping up to 600t of pressure to pack up to 420kg of wool into a bale bound by 10 steel belts.
“It means we can get 20t into a 20-foot container.”
All bales are packed in new high-density polyethylene packs except for Merino, which is usually packed in more expensive nylon.
Water coming off the scour line goes through a high-speed centrifuge that removes dirt and grease before recycling through the plant.
“There’s 35,000 litres continuously recycling through the plant,” Hulme said.
Grease is refined to 98% purity and sold as a raw material for cosmetics, pharmaceuticals, health supplements and animal feeds.
