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Gondwanaland Diamonds, South Africa

 

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Technical and Operational Details
 A Description of How the material is fed through the plant

The current mobile final recovery plant is housed in 3 shipping containers (2.3 x 6 meter) as follows:

CONTAINER 1
container 1container 1b

container 1a container 1b


Alluvial or kimberlite concentrate from a dense medium separation plant, rotary pans or jigs is fed into a first
container feeder bin. The material is fed over a vibratory screen which is a double deck screen, the top deck prevents access to diamonds, where the diamondferous gravel is washed clean of fine material -2mm over the first half of the screen by water sprays and subjected to blowing fans to get rid of excess water over the second half of the vibratory screen. The material then passes over the second screen where it is blow dried using a series of blower fan units. The minus 2mm fines, sludge and water, fall through the screens into the underlying chute and are automatically or manually washed down through the center of the container into a pipe conveyor or into a gravel pump or jet pump which conveys this material to a waste dump. The coarse +2mm material exits the end of the drying screen and is fed away from underneath the first container into the second container by means of a pipe conveyor which also acts as a drier.

CONTAINER 2

container 2a container 2b


The material enters through a port in the side of container 2 so as to feed onto a double deck sizing screen which in turn feeds onto a single deck sizing screen. The screens allow for the screening of the material into the size fractions required for feeding the x-ray machines namely 2-4mm, 4-6mm, 8-16mm and 16-32mm or 2-4mm, 4-6mm, 6-12mm and 12-24mm material. The material fractions pass into the underlying storage bins where the individual gravel size fractions are fed by means of two parallel situated pipe conveyors which exit through the floor of the second container into the underlying VE x-ray machines situated in the underlying container 3.


CONTAINER 3     

diagram 5 and 6

The third container receives the two coarser fractions feeding the VE 113 x-ray machine and the two finer fractions feeding the VE116 machine. As the bottom halves of the material storage bins in the second container are offset where the tapered sections commence (as seen in the side view of container 2) the bins can be turned so that a combination of material sized fractions can be fed into any one of the underlying pipe conveyors and thereafter into the required VE machines.

This versatility allows for accommodating material treated which is predominantly coarse or fine. For treatment of finer material only the VE113 machine can be replaced by a second VE116 machine to increase throughput. Alternatively the VE 116 x-ray six channel machine can be replaced by the newer VE116 twelve channel machine which will double production for these size ranges.

 In the third container the material concentrate generated by the x-ray machines exits through the concentrate chutes either directly into the glove boxes where the diamonds are removed and dropped in a underlying holding safe, or alternatively the concentrate passes directly in the underlying pipe conveyor to be returned via the external pipe conveyor to the security concentrate bin in container 1. From here the concentrate is re-fed (second pass) through the system and x-ray machines. This process drastically reduces the amount of concentrate to be sorted in the glove boxes.

It also allows for secure bulk storage of first stage concentrate for later stage treatment at irregular prescribed intervals by delegated persons when second stage x-ray concentration is required. The waste material after sorting is fed from the a-ray machines via the two underlying pipe conveyors to a dump. The waste material generated after diamond sorting in the glove boxes is reintroduced in the system for re-concentration to prevent diamonds from being purposely discarded with waste material for later recovery. Where build up of extraneous high luminous material apart from diamonds takes place the waste material can be directed into the underlying safes for re-sorting by delegated persons.




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