Vol. 1,
issue #37, 29 September 2000
Vibrocoring from the MV Flat Holm
In August and September, Coastline Surveys Ltd's vessel MV Flat Holm was chartered by Alluvial Mining of Sudbury in the UK to carry out a coring programme in the Bristol Channel in the UK. Alluvial Mining's 3m vibrocorer was mobilised to the Flat Holm and rigged for deployment over the stern using the 5m A-frame.
The 65m2 back deck of the Flat Holm proved an ideal working area for the operation, claims the company. With shallow water and strong tides, the vessel anchored up-tide of the site and veered cable until the stern was within the target area.
Positioning was controlled by Coastline Surveys' Integrated Navigation system using Omnistar DGPS.
Over four working days at four different locations 51 cores were successfully recovered.
MV Flat Holm is 24m long and economical to use, says the company. Now that the viability of operating a vibrocorer from a vessel of this size has been proven, clients can benefit from the reduced cost of the spread and an overall saving on a
project budget.
Further information on the spread can be obtained from either Coastline Surveys at the above address or from Rob Hawkins at Alluvial Mining on 01787 880218.
In addition to the Vibrocoring, a geophysical survey and a successful programme of grab sampling were completed in the same area. The vessel's crane was used to deploy the Hamon grab, and in shallow water a rate of 12 samples per hour was maintained despite unfavourable conditions.
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