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| Bivaud, J. |
| At present, offshore placers are generally exploited by means of traditional dredging equipment. This technique, called the "vertical method," consists of working the seabed directly from the surface support vessel through a rigid upflow pipe equipped, when necessary, with a sediment preloosening system. In contrast with the vertical method, this approach is based on the principle of working along the seabed with transfer of spoil up to the surface after extraction. We therefore call this the "horizontal method." Although it varies according to sites, in most cases this method comprises the design of a vehicle, self-propelled to some degree, which moves along the seafloor, carries and operates the appropriate mining tools and includes a system to transfer... |
| Tipo: Text |
Palavras-chave: Offshore operations; Marine technology; Unmanned vehicles; Mining vessels; Placers; Deep sea mining. |
| Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/1990/acte-1168.pdf |
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| Freitas, A. |
| Service submarines have been developed for support duties in offshore operations in deep waters. Three submarine concepts have been designed for water depths ranging from 400 to 1500 m. The operation philosophy is to use an autonomous manned submarine as a carrier for components, tools and work modules and as a base for IMR operations on subsea installations. The design principles are similar to that of the Space Shuttle incorporating a payload bay, energy supply and a closed environment for the crew and operators. The operation profile of an offshore submarine demands capabilities above those of naval submarines: deep diving, long endurance underwater, dynamic positioning. New technology had to be developed: air-independent energy system, regenerative... |
| Tipo: Text |
Palavras-chave: Dynamic positioning; Marine technology; Diving; Offshore equipment; Offshore operations; Underwater inspection. |
| Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/1990/acte-1165.pdf |
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