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Related to trench: Mariana Trench


see oceanocean,
interconnected mass of saltwater covering 70.78% of the surface of the earth, often called the world ocean. It is subdivided into four (or five) major units that are separated from each other in most cases by the continental masses. See also oceanography.
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in mining, an open excavation in the ground. A trench has a trapezoidal cross section, and its length is many times greater than its width.

Sloping main, or primary, trenches are used in stripping an opencut mine or an individual area of such a mine, and also in establishing a haulage system to link the working levels with the surface. A horizontal, or cross-sectional, trench is designed to establish the initial working front at a bench. In the case of irregular mountain terrain, a trench may have an irregular cross section (hasty trench).

Main trenches are classified on various bases. In terms of their relationship to the contours of the pit, they may be external or internal. They may be of the individual type (providing haulage for a single level), the group type (serving several levels), or the general type (for all working levels in the pit). On the basis of the traffic flow, they are classified as single trenches, with two-way traffic, and paired trenches, with one-way traffic.

The width of a horizontal trench depends on the location of the haulage system and excavation equipment in the horizon being stripped. The depth of a horizontal trench corresponds to the height of the horizon to be stripped. The optimum depth of an inclined main external trench is 50–60 m.

In pits with soft rock, trenches are excavated using multibucket excavators, dragline excavators, or scrapers; single-bucket excavators (trenchers) are used in pits with hard rock. Ejection explosions may be used in digging a trench. If conditions permit, the stripped rock is placed on the surface on one or both sides of the trench; otherwise, it is moved by vehicles to spoil banks.

The rate of excavation of trenches depends largely on the time required for construction of the pit and, in sloped and steeply inclined deposits, also on the productivity of the pit.

Trenches are also used in construction, for the laying of pipelines and cables.



A narrow, straight, elongate, U-shaped valley between two mountain ranges.
A narrow stream-eroded canyon, gulley, or depression with steep sides.
A long, narrow, deep depression of the sea floor, with relatively steep sides. Also known as submarine trench.


2. A housing, 1.
References in periodicals archive ?
In the store are vignettes, including a work area consisting of a work desk and a display of scissors and other instruments used to make the trench.
We company signallers were in communication with no one and Battalion Headquarters who were in the same trench were also in the same plight.
Trench fever, trench foot and trench nephritis were the three big trench diseases.
Shift dresses, with their slim, straight lines, benefit from a belted trench coat which adds shape.
Trench Shore Rentals provides trench shoring equipment, services and supplies in Phoenix and Tucson, Arizona; El Paso, Texas; New Mexico; and San Diego, California.
When OSHA's compliance officers see a trench, they will inspect a trench.
Trench fever was precisely described based on experimental infections in volunteer soldiers (4).
Church was working with a backhoe operator digging a trench for a sewer pipe leading from the last house on a new cul-de-sac near Rancho Vista Elementary School, officials said.
The perspectives created from the bridge and the trench, moreover, offered no view of the collection: The sculptures scattered throughout the park remained hidden in the abundant summer foliage.
Screwjacks, unlike wood shoring, sloping, and trench boxes, do exert outward pressure against trench walls and deter cave-ins.
In 1960, the Mariana Trench saw its first and, to date, last visitors.
The trench was sampled by 5 meter long continuous chip samples along a 480 meter long trench, with samples analyzed for 36 elements by the ICP method.