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HOBART - Special bricks similar to those made by convicts more than 150 years ago for Tasmania's notorious Port Arthur prison are to be used in a A$1 million ($1.2 million) preservation rebuild.
As many as 200,000 new "old" bricks will be used in conservation work on one of the main buildings, known as the Separate Prison.
The Port Arthur prison settlement was established in 1830, built by English convicts and was rated the worst of the worst.
The first 150 convicts worked like slaves in abominable, freezing conditions to establish a timber industry.
The Separate Prison, built between 1848 and 1852, is a rare surviving example of the separate treatment system that moved away from hard labour punishment to a system of reform through isolation.
Life inside was still harsh with prisoners isolated in tiny cells for up to 23 hours a day.
The conservation project in south-east Tasmania includes a reconstruction of the prison's perimeter yard walls.
The decision to reconstruct was based on extensive research and consultation within the heritage conservation industry by the Port Arthur Historic Site Management Authority, said project manager Jo Lyngcoln.
"It's one thing to tell people how this incredibly rare building would have looked and quite another for visitors to experience it for themselves," she said.
"The dominance of the Separate Prison over the Port Arthur landscape can only be translated in this [reconstruction] way."
The Tasmanian-made bricks have a special mix of local clay with a high shale content to reduce shrinkage.
Before being used to reconstruct the walls next February, the bricks will be stored on site to allow them to stabilise, in a process known as grassing.
Lyngcoln said this would allow them to "grow", which they did after firing.
"Normally in every day construction this is not usually a problem, but it is a factor here given the tight engineering tolerances of this project," she said.
Production of the special bricks is just one component of the complex works being undertaken at the Separate Prison between now and June 2008.
Stonemasons have begun stabilising internal corridor walls and dismantling a chimney, which will be rebuilt when the original roof structure has been reinstated.
Some parts of the building are off-limits to visitors.
Thousands of visitors each year are drawn to experience the paradox of the brutal penal settlement in the serene setting of the Tasman Peninsula with its verdant lawns and English oaks.
The state and federal governments have contributed towards the cost of the reconstruction.
AAP
