This cache is one of a series to highlight the history and development at Pentridge, known previously as H.M. Prison Pentridge and now identified as Penal Establishment Pentridge. Caches in this HMPP series are:
- HMPP – H.M. Prison Pentridge (GCAHRT9),
- HMPP – Separate and Silent (GCAHNKT),
- HMPP – Guards Watching (GCAHNDV),
- HMPP – Precinct to work live and play (GCAHTPR),
- The series also includes the H.M. Prison Pentridge Ad Lab.
These caches can be done in any order except for HMPP - Precinct to work, live and play, which requires clues from the other caches.
Prior to 1870 prisoners worked as quarrymen or at other meaningless tasks, forced to do either slave or servent roles. The Stewall Royal Commission conducted a review of Pentridge in 1870. The Royal Commission recommended that:
- Pentridge should try to become self sufficent by establishing industries to produce goods to sell,
- Pentridge had too many warders and should reduce the number, and
- Prisoners are more likely to show 'moral improvement' when they know that they are usefully employed.
The result of this was the building of a Woollen Factory, Tailors and Shoemakers and Carpenters and Blacksmith Workshops (1882). Many of these were made of bricks rather than the bluestone blocks.

Take a walk up Industry lane (ie walk North). The building on the left was originally the Woollen Factory and the Tailors and Shoemakers on the right side. Around 1900 a boiler room existed about half way along (currently a grey building) and the Carpenters and Blacksmith worksop were at the end on the left. At the end of Industry lane was a Store office. As you walk up industry Lane you will need to find the following:
Five lines of text on the roadway. A = the number of letters in the 2nd last word.
The date the woollen factory was built. BCDE = year which is etched into the brickwork.
The building number of the woollen factory. F = large number on a black sign at the front of a square entranceway.
As a bonus you may want to have a look at the Boiler tower at S 37 44.272 E 144 58.123

The boiler tower and boot factory were part of later improvements around 1920s. By this time the industries were highly productive and the prisoners were rewarded for their work. Solitary confinement was phased out as work, and later education, were encouraged.
From the information you have found:
G = B+1, H = A, I = B-F
J = F+1, K = C-D, L=E-C
The cache can be found at:
South 37 44.GHI East 144 58.JKL
Checksum G+H+I+J+K+L = 9
The cache is a small plastic bottle, heavily cammoed. GZ is outside (East) of the bluestone wall and can be busy at times, so stealth may be required. Remember to get the clue for the final cache.