Abstract: In the underground mining of friable mineral deposits such as bituminous sands, method and apparatus are disclosed in which a working crosscut in the mineral deposit, is established, connecting two parallel operating tunnels, the front wall of the crosscut being unsupported and forming the mining wall, the roof and rear wall of the working crosscut being supported by a novel mining shield comprising a plurality of forwardly inclined, base supported arch members positioned in adjacent abutting relationship and each independently advanceable towards the mining wall. A conventional mining machine is employed under the mining shield in the working crosscut, operating across the full width of the mining wall. As the mining machine removes a cut, apparatus upon the mining machine advances individual mining arch sections forwardly into the mining face the depth of the cut, leaving the backs unsupported and free to collapse behind the advancing mining shield.

Abstract: Method for visually checking the lighted condition of a plurality of ground light sources, such as municipal street lighting, by taking a night aerial photograph of an optimum area when all ground lighting in the area is known to be functional, and using such photograph as a master reference for subsequent night aerial photographs of the same area by comparison means. Apparatus is disclosed for upwardly directing a component of each ground light, and altering the quality of such component in order to distinguish.

Abstract: In the underground mining of friable mineral deposits such as bituminous sands, method and apparatus are disclosed in which a working crosscut in the mineral deposit, is established, connecting two parallel operating tunnels, the front wall of the crosscut being unsupported and forming the mining wall, the roof and rear wall of the working crosscut being separated from the mining equipment by a novel mining shield comprising a plurality of forwardly inclined, base supported arch members positioned in adjacent abutting relationship and each independently advanceable towards the mining wall. A conventional mining machine is employed under the mining shield in the working crosscut, operating across the full width of the mining wall. As the mining machine removes a cut, apparatus upon the mining machine advances individual mining arch sections forwardly into the mining face the depth of the cut, leaving the backs unsupported and free to collapse behind the advancing mining shield.