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More modern room and pillar mines use a more "continuous" method, that uses machinery to simultaneously grind off rock and move it to the surface. [12] Other processes, such as backfill, where discarded tailings are unloaded into mined-out areas, [9] can be used, but are not required. Retreat mining (below) is an example of a process like this.
Continuous mining utilizes a continuous miner machine with a large rotating steel drum equipped with tungsten carbide picks that scrape coal from the seam. Operating in a "room and pillar", also known as "bord and pillar" system, where the mine is divided into a series of 20-to-30-foot (5–10 m) "rooms" or work areas cut into the coalbed—it ...
For example, a pressure fluctuation of 20psi (or less) can be “picked out” of a total mud system pressure of 3,500psi or more. [ citation needed ] Downhole electrical and mechanical power is provided by downhole turbine systems, which use the energy of the “mud” flow, battery units (lithium), or a combination of both.
In physics, for example, the space-time continuum model describes space and time as part of the same continuum rather than as separate entities. A spectrum in physics, such as the electromagnetic spectrum, is often termed as either continuous (with energy at all wavelengths) or discrete (energy at only certain wavelengths).
The Siilinjärvi carbonatite complex, [1] an open-pit mine owned by Yara International, in Siilinjärvi, Finland Coal strip mine in Wyoming. Surface mining, including strip mining, open-pit mining and mountaintop removal mining, is a broad category of mining in which soil and rock overlying the mineral deposit (the overburden) are removed, in contrast to underground mining, in which the ...
The British imperial system uses a stone of 14 lb, a long hundredweight of 112 lb and a long ton of 2,240 lb. The stone is not a measurement of weight used in the US. The US customary system uses the short hundredweight of 100 lb and short ton of 2,000 lb. Where these systems most notably differ is in their units of volume.
The Rössler attractor (/ ˈ r ɒ s l ər /) is the attractor for the Rössler system, a system of three non-linear ordinary differential equations originally studied by Otto Rössler in the 1970s. [ 1 ] [ 2 ] These differential equations define a continuous-time dynamical system that exhibits chaotic dynamics associated with the fractal ...
The concept of a continuum underlies the mathematical framework for studying large-scale forces and deformations in materials. Although materials are composed of discrete atoms and molecules, separated by empty space or microscopic cracks and crystallographic defects, physical phenomena can often be modeled by considering a substance distributed throughout some region of space.