A Treatise on Coal Mining, Volum 2,Deler 11-21Colliery engineer Company, 1900 |
Vanlige uttrykk og setninger
anthracite anticlinal beds belt bituminous bituminous coal body breast cage carbon Carboniferous cars center of gravity chute clay coal field coal measures coal seam cross-cuts curb depth Devonian direction distance district drill driven equal face fault feet thick force fossils friction gangway haulage headings heat hoisting hole horizontal horsepower inclined iron length lever limestone load longwall manway material method miner mining number of revolutions number of teeth opening outcrop packwalls parallel pillars pitch placed plane pounds pressure props pulley pumping punch blocks rail result revolutions per minute right angles roads rocks roof rope sand sandstone shaft bottom shale shown in Fig shows side Silurian sinking slope sometimes specific gravity square inch strata surface syncline taken timber tion track trepan tubbing tubes upper velocity vertical walling wedging weight width wire wrought iron
Populære avsnitt
Side 36 - ... specific gravity — as applied to wood, the ratio of the ovendry weight of a sample to the weight of a volume of water equal to the volume of the sample at some specific moisture content, as green, air-dry, or ovendry.
Side 2 - The heat which is expended in changing a body from the solid to the liquid state, or from the liquid to the gaseous state, is called latent heat.
Side 53 - Law. — The temperature remaining the same, the volume of a given quantity of gas varies inversely as the pressure.
Side 9 - Every motion or change of motion is proportional to the acting force, and takes place in the direction of the straight line along which the force acts. (3) To every action there is always opposed an equal and contrary reaction.
Side 2 - The pressure upon the bottom of a vessel containing a fluid is independent of the shape of the vessel, and is equal to the weight of a prism of the fluid whose base is the...
Side 26 - ... apart. These headings are continued on either side of the chutes until they intersect the breasts. When the chute and headings are finished, the work of getting the coal in the panel is begun by going to the end of the uppermost heading and widening it out on the rise side until the airway above is reached and a working face oblique to the heading is formed. This face is then drawn back to the chute in the middle of the panel. After the working face...
Side 9 - All bodies continue in a state of rest, or of uniform motion in a straight line, unless acted upon by some external force that compels a change.
Side 9 - That is, the upward pressure exceeds the downward pressure by the weight of a volume of water equal to the volume of the body.
Side 44 - There are three undetermined points in this connection, viz. : 1. The maximum distance between the two beds, or the length of rock chute that can be driven with satisfactory financial results. 2. The maximum dip on which such working can be successfully opened.