Marine and Mineral Projects - Deep Sea Mining Equipment

South African deep-sea mining engineers, Marine and Mineral Projects (MMP) have developed world-leading technology for deep-sea mining from support vessels. They utilise subsea remote-controlled underwater crawlers, launch and recovery systems and mooring systems to enable cost-effective diamond and mineral offshore mining.

MMP is based in South Africa but operates internationally, supplying equipment to a range of international mining projects in the UK, Europe, Russia, Brazil and Australasia. All systems are provided with Classification Society (Lloyd’s Register, DNV, ABS, RINA, etc) approval as required by the client.

SUB SEA CRAWLER MINING SYSTEM

The sub sea crawler mining system is a deep sea tracked mining tool, attached to the vessel by a wire rope and an umbilical that provides power and remote control. The controllers of the vessel operate and monitor the underwater crawler’s progress from onboard. This is done through the use of special control chairs computer monitors that provide readings on oil, power and water levels, pressures and temperatures. Production is enhanced with a virtual animation of the movements of the crawler, the seabed and the mining process.

The crawlers weigh 250t and comprise 110t of heavy wall pipe and steel construction and 140t of equipment and machinery. The pump on the crawler sucks materials from the seabed and draws them to the water's surface. The riser pipe (through which the mined material travels) is 650mm in internal diameter and can handle spheres of up to 300mm. The material's journey from seabed to surface takes just 25 seconds.

A filter nozzle (fitted to the suction mouth of the crawler’s vacuum pipe) only allows particles of a certain size through. The pilots can adjust the speed at which the vacuum pump operates – depending on the consistency of the material on the sea bed, (which can vary from fine silt and sand to rocks and boulders) optimising production rates.

DEEP SEA MINING CRAWLER

MMP is in the process of adapting its deep sea mining crawler technology making it suitable for the mining of subsea massive sulphides and underwater heavy minerals in at water depths of up to 3,000m.

SUBSEA CRAWLER LAUNCH AND RECOVERY SYSTEM

The Crawler Launch and Recovery System (LARS) consist of an A-frame, swell compensator, hoist winch and umbilical winch. This system is used to deploy and recover the crawler from the vessel deck to the ocean floor.

Due to the dynamics of the system (vessel motion) the hoist winch allows for render in the event of the crawler being stuck on the sea bed or in the event of a snatch on the wire rope due to unusual wave conditions. This is achieved through the introduction of a variable clutch system that will manage the wire under high load conditions. This means that the wire rope and crawler are protected in extreme circumstances, preventing wire breaks and crawler damage.

The crawler umbilical that provides power, control and oils is stored and managed by the umbilical system comprised of an umbilical winch and powered sheave. This umbilical winch is complete with oil, electrical and optical slip rings to ensure continuous operation during the entire launching / recovery and mining processes of the crawler.

MOORING WINCHES FOR DEEP SEA MINING

A four point dynamic mooring winch system has been developed by MMP to ensure that during the launching and recovery of the crawler, as well as while the crawler is operating on the sea bed, the vessel remains on station.

This system allows the vessel to hold steady station on a four-anchor spread. A further benefit of the system is that it does not require an anchor-handling tug to assist with spread laying.