Abstract: A method of determining the gas leakage through a mine stopping. The mine stopping, whose leakage is to be measured, is set up in a mine. Next, a test barrier is set up in the mine adjacent to the stopping. The volume between these two structures forms a closed test chamber filled with ambient gas. A known trace gas different from the ambient gas or a known contaminating gas is introduced into the chamber and mixed therein. Thereafter, periodic measurements are made of the rate of change in concentration of the tracer gas. Lastly, based upon the measured rate of change in concentration of the tracer gas, the leakage past the mine stopping is determined.

Abstract: A method of forming a prechar-layer on wood to cause it to become fire and rot retardant. In an air or a low oxygen concentration atmosphere the wood is uniformly charred at a depth of at least 3 millimeters by a high-intensity radiant heat panel. Normally the heat panel is spaced from and moved with respect to the wood. The relative velocity of the wood past the radiant panel and the panel's emitted heat flux are used to control the depth of charring. Preferably fire and/or rot retard chemicals and/or treatments are added to the formed charred layer to further increase the wood's fire and rot retardancy.

Abstract: A lock-out control logic circuit for a feedback inverter system, which senses the load current in each load switching element of the inverter system and utilizes the sensed current through the presently conducting load switching element to inhibit the next firing of the presently non-conducting load switching element. Current transformers are inserted in series with each switching element and coupled to a CMOS logic circuit which inhibits the firing pulse to a non-conducting load switching element in the event a current conduction condition is sensed.

Abstract: A portable hard rock crusher unit especially useful for low clearance underground mines. Material to be crushed is horizontally fed to the rotary crusher jaws. A curved convergent material flow-path is employed between two crusher jaws. The outer member of the crusher is a substantially stationary outer curved concave jaw and its inner jaw member is a cylindrical element mounted to give eccentric motion on a shaft. The inner member may freely rotate on its eccentric or it may also be rotatably driven. Material fed between the inner and outer jaw members of the crusher encounters a progressively narrower opening as it is crushed and moved by the peristaltic pumping action caused by the eccentric motion of the movable inner crusher element acting against the outer stationary jaw.

Abstract: An apparatus for non-destructively testing concrete comprises a tri-wheel platform having a transducer mounted adjacent each wheel and mechanically coupled to the concrete to be responsive to vibration. An aperture is formed in the center of the platform equispaced from the three transducers. Vibrations are imparted to the concrete that emanate outwardly toward the transducers by manually striking the concrete through the center aperture with a rubber tipped impact rod. The transducers generate electrical signals responsive to the amplitudes of detected vibrations which are a function of the structural continuity of the concrete. Electronic circuitry monitors the outputs of the transducers and makes comparisons of the signals to determine whether a flaw exists in the concrete within the region bounded by the three transducers.

Abstract: A vibrating wire stress meter. The wire is highly tensioned diametrically across the sides of a hollow metallic cylinder and held there by two anchor tubes. A wedge and platen assembly in turn hold this cylinder in a rock borehole such that small stress changes in the surrounding rock cause the diameter of the cylinder to slightly change. This cylinder variation is transmitted to and measured by the preloaded wire by noting variations in its frequency or period of vibration. To cause the wire to vibrate a coil, magnet, and yoke are used as a plural pole electromagnetic plucker.Clamping of the wire is accomplished by highly tensioning the wire between two opposite hollow tubes that are seated in opposite aligned countersunk holes of the cylinder and then extruding the steel tubes around the wire. The wire extends through holes of those hollow tubes as well as the aligned holes in the cylinder walls which are diametrically opposite each other.

Abstract: A method of agglomerating fine ore powders. The invention is used to agglomerate extremely fine flue dust particles in a collection bin and process them before sending the resultant agglomeration to storage or a further processing location. From its collection bin, the dust particles are discharged by gravity upon a lower rapidly rotating smooth horizontal disc. The bin discharge is offset slightly from the disc's center so that the particles are subjected to centrifugal force to move them to the disc's outer periphery. At the point where the particles are discharged on the disc, a liquid binder, like water, is sprayed on the particles to cause them to begin to agglomerate. After being sprayed, the wetted particles are agglomerated under the influence of centrifugal and tangential forces. A scraper may be used to aid in pushing the particles towards the disc's raised outer edge.

Abstract: A coal mine ventilation system which insures proper ventilation near the working area. The basic system employs a mining machine on which is mounted a panel on a movable frame, a conventional line curtain fixed to the mine floor and roof and located adjacent to the panel, and an air control fluid spray system. Fluid sprays may be mounted on the machine on the opposite the panel to promote airflow towards the mining face. Additional sprays may be mounted on the machine panel to provide an effective barrier between that panel and the fixed line curtain.

Abstract: An infrared radiation measuring pyrometer whose output is used to calculate both particle and gas temperatures from an explosion or fire. Preferably four infrared wavelength measurements are made to compute the particle temperature and two infrared wavelength measurements to compute the gas temperature. Especially constructed to operate in an explosion environment, the invention allows the simultaneous and continuous measurements for both particle and gas temperatures. Planck's Law is used to relate the radiation emitted from the particles and/or gas to the wavelengths observed, the emissivity of the object at that wavelength, and the temperature of the particles and/or gas. For each specific wavelength detected at the pyrometer there is an output voltage which can be related to the flame radiation.

Abstract: A high voltage measuring device used to measure the amount of voltage in an alternating current carrying line. When in use no connections or physical contact are made between the line and the measuring device. Generally, the measuring device acts according to the capacitor divider principle with two capacitors. One electrode of one capacitor is the high voltage line itself and the other electrode of this same capacitor is a spaced flat circular plate located on the measuring device. The measuring device electrode is insulated near its periphery and connected to a low voltage capacitor having a low loss and good temperature coefficient. This capacitor forms the other part of the capacitor divider.

Abstract: An improved method of solution well mining is provided which, among other advantages, enhances the injectivity of the wells and eliminates the need for underreaming and the use of well screens. In solution well mining, a leaching solution is pumped into an injection well so as to flow through a mineralized zone to a plurality of production wells, the solution which contains the mineral to be recovered being pumped out of the production wells. The invention provides for using a high pressure water jet to perforate the cemented casings of the well so as to, inter alia, enhance injectivity and provide sand control. The perforations are arranged in a preselected nonuniform pattern in the production well, with the density being the greatest at the bottom of the zone, so as to promote uniform flow of the solution.

Abstract: The sensing mechanism of the present invention includes a probe electrically connected to a mine roof bolting apparatus and adapted to be embedded within a mine roof to sense any shifting of the apparatus during an operative cycle. The probe is linked to a 360.degree. rotational toggle switch mechanism which controls an alarm means. The probe is pivotably mounted within the roof bolting apparatus and consequently, any effective movement of the apparatus along any direction within a horizontal plane pivotably displaces the probe and actuates the switch mechanism, energizing the alarm. In this manner, personnel are apprised of conditions warranting corrective measures in order to re-position the bolting apparatus or the apparatus may be automatically halted so as to prevent damage from being imparted thereto.

Abstract: A loading gate for a mine roof bolter apparatus forms a protective canopy for mine working personnel when opened, and when closed, it seals an opening in the bolter containing manual controls and roof bolt storage cartridges. Access to the stored cartridges and controls by the personnel can only be made when the gate is open. The gate is operated by an over-center toggle joint driven by a hydraulic cylinder. As a fail-safe feature, once the gate has been fully opened, the over-center toggle joint maintains the gate open even upon failure of the hydraulic cylinder.

Abstract: A load measuring gage generally shaped like a conventional split ring washer. In the center opening of the gage a shaft, which mounts the device whose load is to be measured, may extend through the washer. The opening for the washer is cut diagonally so that the loading and unloading forces acting upon it are collinear thereby reducing friction that resist its opening and closing to a minimum. This is accomplished by orienting the angle between the split ring surface and adjacent bearing surface to be between 50.degree. and 62.degree.. A force indicating pointer and scale can be attached to the washer to inform observers visually of variations in the force applied to the gage. In this way if the tension on a mine rock bolt is being measured, observers may safely be informed of the force on the in situ bolt from a distance.

Abstract: A Frequency Shift Keying (FSK) system to transmit and receive data as a sequence of dual frequency short duration tone bursts. Normally the data is transmitted from an underground location, as in a mine, to the surface or to another underground location. At the receiving end the transmitted data is detected as marks or spaces that are used to clock the appropriate data bits into a storage shift register. Erroneous data from wideband noise transients at the receiver are eliminated by the use of an exclusive OR circuit which permits shift pulses to appear at the data register only when one or the other of the two shift pulses are present but not both. To further insure accurate copy of the digital data at the receiver, a receiver alert code is transmitted prior to the telemetering of the actual data. Only after recognition of the receiver alert code is the receiver able to receive the transmitted data bit stream.

Abstract: A tiltmeter which uses two fluids of different thermal density coefficients, each of which is contained in its own fluid system consisting of a long tube connecting two vertical reservoirs. The two systems are deployed in physical contact along their entire length so that they experience the same thermal conditions. Measurements with this instrument are made by taking separate, simultaneous readings of the difference in fluid heights and/or bottom fluid pressure between the terminal vertical reservoirs in each of the two fluid systems; these measurements, together with known density coefficients of the fluids, provide the data to correct for errors in meter readings caused by temperature/density fluctuations in the fluids and permit a precise determination of vertical displacement and tilt over the measurement path. The ruggedness and unique design of this tiltmeter allow it to make more accurate measurements of regional tilt than previous tiltmeters and with less expenditure of money and effort.

Abstract: A muffler for a percussive drill is provided consisting of a casing of general prismatic shape adapted for mounting on the drill. An inlet is present in the casing for receiving exhaust from the drill, the drill exhaust port and muffler inlet having the same cross-sectional area. Resilient rectangular baffles are mounted within the casing and are rigidly fastened at two opposite edges to the casing wall. The two other edges, which are longer than the fastened edges, are in contact with casing walls. Staggered holes are present in the baffles, so the gas flow through the muffler follows a sinusoidal path. The sides of the casing tapers down after the last baffle to a fraction of its height and then extend for a given length at the lessened height to form a narrow rectangular exhaust port. One face of the casing adjacent the exhaust port consists of resilient sheet material. The flow of gas through the muffler causes strong vibration of the baffles and resilient face near the exhaust port.

Abstract: In an apparatus for installing resin anchored roof bolts in a mine roof, continuous bolt material is stored on a spool rotatably mounted on a mobile roof bolter frame. As the apparatus advances along the mine passageway, the bolt material is uncoiled from the spool and guided upwardly into spaced apart, resin filled holes that are preformed in the mine roof. The bolt material is severed just beneath the roof at each hole to form a unitary roof bolt. A stop is formed in the unitary bolt with a hydraulically operated head and mandrel mechanism that makes a right angle bend in the bolt just beneath the mine roof.

Abstract: A square hole drill having a cutterhead configuration whose outline is in the form of a Reuleaux triangle and which also has a planetary gear drive. Two counter revolving motions are present in the drill at the same time. One is the pure rotary motion of the drill's cutterhead about its own shaft. The other is the circular motion of the cutterhead as a unit about a center line due to its eccentric mounting and drive. To achieve the opposite rotation of the unit as a whole compared to the rotation of the cutterhead about its own axis, a combined meshing planet gear and ring gear are used. The planet gear is directly connected to the cutterhead by a shaft rigidly attached to the gear's front side. At the rear side of the planet gear is the eccentrically mounted drive shaft. Surrounding the external teeth of the planet gear is a larger stationary ring gear with internal teeth to continuously engage the planet gear's teeth.

Abstract: A method and the apparatus for implementing the method to provide temporary ground support in a mine. After an auger or other type of hole has been bored in an underground mine, at least one inflatable bladder with a fluid conduit therethrough is inserted into the hole. Once the bladder is inflated it expands to fill the hole's diameter and to act as a plug. Thereafter, fluid is forced through the fluid conduit past the bladder and into the hole cavity to act in conjunction with the bladder as a ground support for the hole. Appropriate fluid valves, meters, and conduits are placed at the input to the fluid conduit to control and measure the fluid being forced into the bladder and the hole cavity. Quick connect-disconnect couplings are provided when two or more bladders are connected seriatim and placed within the hole.