Diamonds are..

Following on from the visit to the Platinum mine, the following day I headed out to the site where the world's largest diamond was found, Cullinan. Cullinan is about an hours drive north east of Pretoria and is an otherwise quite country town, surviving on the back of the diamond mine. The mine itself is surrounded by a mining small village, hospital and fire station; it was interesting to learn that during the early 1900's miners would be required to "living-in" in an attempt to control theft. The mine is over 100 year old and has produced a significant amount of the world's diamonds including the largest which was named the "Cullinan diamond" and is now part of the British crown jewells.
Original production was from an opencut that eventually reached 400m in depth, before underground methods were used. Current depth is 800m bellow surface and uses a modified sub level caving method. The shear size and grandure of the mine is nothing like I have ever seen before, with the workshops and lunch room underground being very well apointed and even includes a fish pond.

Survey methods at the mine include real time monitoring of a nearby road using extensiometers and tilt meters, GPS monitoring of the highwall and fine dam, in addition to the typical control surveys, drivage and grade control. Due to the age of the mine some of the original plans for the area over 100 years old and impressive to see especially the draftsmanship, sadly the one thing that modern drafting lacks.

Back to survey reality here as the team consists of a 3 surveyors and 3 assistants. For a while there I thought every mine had scores of assistants.