Technical
Bonaparte is one of very few companies internationally, that owns and operates a technically proven marine diamond sampling system. This system comprises the Bonaparte Seabed Sampler (BoSS) and a modular materials processing and recovery plant.
The BoSS has 5.0m overall length with a sample area (footprint) of 1.13m2 and an effective seabed penetration depth of up to 5.0m, which can be extended if required. The seabed sampler operates using compressed air to create a strong suction at the seabed end. High pressure water is used to liberate seabed sediments which are then sucked into the sampler and transported to the sampling vessel through the slurry hose which feeds into the primary processing unit. Particles up to approximately 100mm in size are transported to the surface in this way. An integral part of the operation of the BoSS is the heave compensating tower. This is a 5 m high tower used to keep the hoist wire under constant tension to compensate for the vessel movement and keep the sampler upright and on the seabed in swell conditions up to 4m.
The materials processing and recovery plant can be divided into two parts namely a primary and secondary processing units. The primary module facilitates de-aeration, de-watering and screening of the slurry. It is designed to screen up to 600m3/hr of slurry delivered from the seabed by the BoSS and to gather material in the size range of 1.5mm-12.0mm for secondary processing. The screening module automatically sizes material into two size fractions; 1.5-4mm and 4-12mm which are stored in separate bins for transfer to the secondary processing/diamond recovery unit. The secondary processing unit receives and treats the screened material for onsite diamond recovery using an x-ray sorting machine. Recovered x-ray concentrate is then hand sorted within the units secure facility to recover diamonds.
The sampling system was designed with a by pass and bagging facility to allow sample recovery and primary processing to continue independently from the secondary processing and diamond recovery operations so that a high sampling rate can be maintained. The real time availability of sampling results gives the ability to carry out dynamic management of exploration activities, using the results of daily sampling to assess and plan the sampling programme for the following day. In this way the sampling operation can be optimised.
The system comprises existing technologies that have been proven in the marine diamond industry off the west coast of southern Africa. These proven technologies were configured with smart engineering design, to produce a low cost, effective and quantitative sampling system. The modular, stand-alone design has resulted in a marine sampling system that can be easily transported and which allows for relatively quick, deck-based installation (mobilisation/ demobilisation) on vessels of opportunity. This modular design eliminates the requirements for costly, long term vessel charter and/or purchase agreements.