Abstract: A collar which has the comfort and fit of typical adjustable collars and yet is tightenable under tension and releasable when tension is released so as to provide obedience and control typical of choke collars. The collar includes first and second straps and first and second side mounted side brackets. The first strap is attached at each end thereof to one end of each side bracket and is adapted to extend across the forward portion of the animal's throat. The second strap is attached at a first end to the first side bracket and extends about the rear of the throat of the animal, through the second bracket, across the first strap, again through the first bracket to terminate at a second end thereof in an attachment to the second bracket. A rearwardly directed force on the outermost rear portion of the second strap initiates a sliding of the second strap relative to the first and second brackets and the first strap so as to reduce the diameter of the throat receiving opening defined by the collar structure.

Abstract: A drilling head for use in mining operations comprises a cylindrical drum having an open rear end and defining an interior cavity, an exterior spiral arranged to forwardly advance mined particles, a nose spiral disposed in advance of the drum and arranged so as to rearwardly advance the mined particles, the exterior and nose spirals terminating generally at the front portion of the drum and together defining at least one recovery aperture through which the mined particles forwardly advanced by the exterior spiral and rearwardly advanced by the nose spiral can pass to the interior cavity, and an interior spiral coaxially disposed and rotatable in the interior cavity in a direction opposing the rotational direction of the drum.

Abstract: A drilling head for use in mining operations comprises a cylindrical drum having an open rear end and defining an interior cavity, an exterior spiral arranged to forwardly advance mined particles, a nose spiral disposed in advance of the drum and arranged so as to rearwardly advance the mined particles, the exterior and nose spirals terminating generally at the front portion of the drum and together defining at least one recovery aperture through which the mined particles forwardly advanced by the exterior spiral and rearwardly advanced by the nose spiral can pass to the interior cavity, and an interior spiral disposed so as to rearwardly advance the particles which pass through the recovery aperture. An assembly of counter rotating drilling heads is also disclosed.