Blackbutt Reserve is an area of preserved bushland following past mining activities. Now a recreation area consisting of walking trails and picnic areas, also a pretty well stocked fauna display.
To find the cache - make your way to WP1: you can drive up to and park within 50m. At WP1 is a green sign. Consider A=1, B=2 and so on to Z=26 for these calculations. Adjustments below are made to the decimal portion only of the listed coordinates for WP1, unless you feel like a drive up to Gloucester!
Calculate the sum of the first 5 letters of either the 6th or 7th word on the sign (should be the same number!) - subtract this number from the latitude coordinate.
Take the value of the first letter of the 7th or 9th word - add this to the longitude coordinate.
The adjusted coordinates will take you to the cache.
Under the tree canopy here, the GPSr wasn't the best, give your GPSr time to settle. Coordinates were averaged on two visits here, 10-15 minutes each time.