B. N. Smolyanitsky

Downhole high-pressure air hammers for open pit mining

The energy upside potential of downhole air hammers is considered. The article presents the constructional diagram of a new air hammer using high compressed air pressure (up to 3 MPa). The experimental testing of the operating cycle of the air hammer is reported. The authors ascertain the air hammer steel requirements and the steel heat treatment modes to enable extended life of the air hammer parts. Industrial trials of the air hammers are described.

Effect of blow frequency and additional static force on the vibro-percussion pipe penetration rate in soil

The authors describe and discuss experimental investigation of the effect exerted by blow frequency and additional static force on penetration rate of a pipe under vibration-percussion by a pneumatic hammer with using a measuring and recording instrumentation developed at the Institute of Mining, Siberian Branch, Russian Academy of Sciences. The penetration velocity ranges are found for the real blow frequencies of the test pneumatic hammer equipped with additional static load. Determination of static force sufficient to press the pipe in soil in hammer-free regime is reported.

Enhancement of energy carrier performance in air hammers in underground construction

The article concerns with the problem of blow energy increase at the confined air consumption in air hammers used in special underground construction. The solution is the air distribution circuit with an elastic ring valve installed in the back stroke chamber; the valve is closed under mechanical contact with the air hammer housing and opens under action of the elastic force of the material the valve is made of. The use of such valve enables relief of the backward pressure during the direct stroke of the hammer and allows the back stroke length adjustment, which ensures the constant blow energy at the varied air flow.

Determination of conditions for compressed air-assisted removal of plastic soil in horizontal pipeline in drilling

Under discussion is plastic soil removal in horizontal rotating pipeline by air flow. It is experimentally proved possible to remove soil by batches generated during rotation of the pipeline. The found relationship between soil conveying in the pipeline, the pipeline diameter and air forward pressure is made the basis for determination of the parameters of the main transporting line in a drilling installation.

Concerted operation of pneumatic percussion tool and air-aided chips removal line in horizontal hole drilling machines

The authors study work process of pneumatic percussion units with valveless air distribution under exhaust back pressure in drilled solid removal line in long horizontal hole drilling machines. It is shown that range of efficient values of the machine performance equal to maximum percussion force does not change under increase in the exhaust back pressure.

Experimental substantiation of broken soil transportation in horizontal borehole drilling

The authors experimentally confirm the efficiency of the pneumatic transportation of broken soil through a horizontal rotary pipeline in the horizontal hole-making in soil under the integrated effect of a drilling machine.

Borehole Driving with Pneumatic Punchers and Impact Devices Having an Annular Instrument

Substantiation is provided for a method of forming boreholes in which part of the soil is removed from the borehole and part is displaced into the mass. Interaction between the pneumatic puncher and the soil is examined, when the pneumatic puncher is used with an impact device having an annular instrument. Calculated relations are obtained to determine the rate of driving of the borehole.

Promising Mining Technologies for Gold Placers in Transbaikalia

The discussed basic features of geology of gold placers in Transbaikalia include: long extent, occurrence of a gold pay streak nearby gutter, small thickness of a gold pay streak and deep occurrence sometimes, majority of fine flattened gold particles. It is suggested to enhance development of such placers using new engineering solutions. It is recommended to carry out flushing by means of technologies based on the combination of flotation and gravity concentration followed by activation leaching of gold from concentrates and bullion minerals–gold concentrators. A new leaching technology offered for deep-seated placers involves pre-drainage of a pay streak, saturation of the pay streak with photoelectron-activated concentrated solutions and, finally, electrodiffusion leaching of gold.

Improvement of Pipe Pushing Method

In focus is improvement of hole-making technology by vibro hammer pushing with batch-wise removal of soil core while a pipe is driven in soil under impact loading. The important advantage of the technology is the concurrent pipe driving and soil core removal. The minimal air pressure required to separate a core and transport it along the pipe is determined. The frequency of soil core separation and transport during vibro-hammer driving of pipes in soil has been tested in underground construction of utilities. The tests prove the possibility to cut-down time of trenchless construction of underground passages and to raise the level of mechanization of the operations.

Evaluation of Layout of Air Drill Hammer with Smooth Adjustment of Impact Impulse Frequency

Design of an air drill hammer with the smooth adjustment of the percussion frequency at the constant blow energy is considered. The proposed and analyzed modifications of air distribution system are based on using a mechanically closing elastic valve. The test data on experimental prototypes of the air drill hammer with the external distributing elements that set blow frequency are presented. The frequency adjustment ranges are determined.