The Sub-Sea Hydrojet Rock Trenching System -

The Miah Hydrojet Underwater Rock Trencher is a high production Trenching System and a dramatic improvement over present conventional methods of excavating rock in the ocean floor for purposes of burying pipelines, submarine electrical
cables, fibre optic cables, etc. Present subsurface excavation methods in solid rock include dredging, ripping and blasting,which in many cases extensively disturb the biological environment in which they are utilized. One major objective in developing The Miah Underwater Trenching System included reducing environmental damage while subsurface work is being accomplished and to be able to restore the ocean floor to close as possible to its natural state. 

 Another objective was to provide a ocean floor rock trenching system more efficient and productive 

than conventional methods. This trenching system has successfully trenched hundreds of kilometers around the world. The rock trenching sled is basically comprised of a hydraulically driven cutter assembly mounted on a sturdy steel structured foundation which is pulled along the ocean floor during operation by a barge on the surface and assisted by the Miah Powered Stabilizer Chassis tracking behind the cutter chain in the trench bottom.  Power is supplied by a power unit mounted on the vessel through an umbilical to the rock trenching sled. The sled is equipped with a high pressure water injector system which removes overburden on top of the solid rock strata enabling the sled to sit on the rock surface.

The rock trenching sled is basically comprised of a hydraulically driven cutter assembly mounted on a 

sturdy steel structured foundation which is pulled along the ocean floor during operation by a barge on the
surface and assisted by the Miah Powered Stabilizer Chassis tracking behind the cutter chain in the trench bottom.
Power is supplied by a power unit mounted on the vessel through an umbilical to the rock trenching sled. The sled
is equipped with a high pressure water injector system which removes overburden on top of the solid rock strata
enabling the sled to sit on the rock surface.

The rock cutter head trenches down into the rock from the rock surface. The Miah Trenching System is utilized in
conjunction with a more conventional water injector unit which will clean the trench and lay the electrical cable
and/or pipe in a separate operation. Water currents will carry sediments into the trench to cover the utility and
keep it in place. The well defined ditch configuration produced by the rock trencher will perfectly confine the
cable or pipe protecting it from drift, iceberg scouring, dragging anchors and fishing gear. The actual trenching
activity will take place within the housing of the sled which will confine the sediments keeping the surrounding
environment from being disturbed.

This system can be utilized with the Miah Prefatigue Trenching System with the Powered Stabilizer Chassis.

HYDRO-JET ROCK TRENCHER