Originally, the roll weighed 12 tonnes, but is now a little less as over its 47 years of life; it had some 50mm ground off its diameter. It is seven metres long and 750mm in diameter.The roll was the top roll in the first press and was loaded with some 250 pounds per lineal inch against the bottom roll to form a nip through which the felt with the wet sheet passed. The sheet follows the granite roll as it exits the nip and is then pulled off the roll as it continues on to the second press and dryers. As it passes through the loaded nip, water is taken from the wet sheet by the fe
lt to dry the sheet.
Granite is a composite rock comprising a matrix of quartz, mica and feldspar; and has good properties in that the surface contains lots of pores where the mica is present. Capillary action causes the water to cling to the roll, making it easy for the damp sheet to peel off the surface without breaking.
Unfortunately, this roll had developed a crack and had to be condemned and replaced with a more modern roll with an engineered ceramic surface to replicate the properties of the original granite. B10 has a second granite roll which is currently inservice, and will be retained as an emergency spare.
The Big Roll A Recycling Initiative
How do we dispose of a fractured granite roll? This was the question raised recently about B10 paper machine’s first press top roll which needed replacing and disposal. Karen Pascoe (Environmental Specialist Tasmania) and Peter Schnackenberg (Senior Mechanical Engineer Burnie) provided tis good news story
It’s often a case of being at the right place at the right time. Originally it was felt that the fractured granite roll would need to be taken to the Burnie rubbish disposal site, but with a few ‘phone 
calls, we not only found a much nicer home for the roll; we also took the recycling message to the max!
As you may be aware, The Makers Workshop at Burnie is in the final stages of construction. This building incorporates Creative Paper within a newly developed tourist precinct. A few ‘phone
calls were made, a picture of the machine roll was sent to the Burnie City Council, and within a couple of days, landscaping plans were adjusted to include the machine roll.
Tasmanian Paper is delighted that the roll could form part of the ‘street art’ in this precinct. The added bonus is that it has been placed near the southern entrance of 
the Makers Workshop, with maximum
visual exposure from passing traffic.
This is a win-win situation for everyone. Not only do we recycle - to the benefit of the community of Burnie - something which we can no longer use, but tourists can also share in our heritage.
Following completion of the area, a plaque will be placed near the roll explaining its use and history. Queensland has the Big Pineapple; well Burnie now has the Big Roll!
The technical drawing of the Granite Roll Assembly may be viewed at the Makers Workshop on request
Text and images Courtest of "Tas Paper Tasinews." issue 328, Oct-Nov 2010
