Vol 71 Iss. 2

Modern geological exploration service is characterized by a developed technical base, in which an important role is played by such complex works as drilling of wells and sinking of mine workings ....

Developing at an unprecedented pace, our national economy sets before the geological service large and responsible tasks of identifying and preparing for transfer to mining organizations new mineral deposits and expanding those already being exploited ....

Successes in the synthesis of new superhard materials, in particular, cubic boron nitride (elboron), which has increased heat resistance compared to natural diamond and hard alloy (respectively 1.8 and 1.6 times) and chemical inertness to ferrous compounds, opened wide opportunities to expand and improve the raw material base for the manufacture of drilling rock-destroying tools ...

In percussive drilling the rock at the bottom of the hole is destroyed by a falling bit with a percussion rod screwed on it. Potential energy stored during the rise of the projectile to a certain height is used to do useful work - breaking the rock ...

Recently, in many countries, interest in the use of mineral resources of the seas and oceans has been increasing. Modern technology allows the development of underwater deposits of many minerals. As a rule, these are placers located at shallow depths (up to 50-100 m).

Thermal method of drilling through snow and firn and ice deposits in hard-to-reach areas has a number of advantages over conventional mechanical drilling methods. It does not require heavy equipment and large energy costs, provides high quality and 100% core yield, which can be used for a wide range of studies: glaciological, petrographic, crystallomorphological, geochemical, etc. ....

For engineering geology it is very important to take samples of soil with undisturbed structure. Especially difficult in this respect is the sampling of monoliths from frozen soils in the process of borehole sinking. In order to work out the technology of drilling wells in frozen soils, experiments were set up, in the course of which the main difficulty was the choice of a method of control over the state of structure preservation in the process of drilling ...

With the increase in drilling depths the borehole drilling in glacial cover becomes sharply complicated, as the borehole continuously narrows due to ice creep under conditions of increasing rock pressure and temperature. Thus, during deep drilling at the Vostok station in Antarctica, ice creep became apparent from a depth of 500 m at an ice temperature of –53°C. ...

Drilling for phosphorite exploration in the ESSR is characterized by the lack of a reliable method for obtaining cores of shell sandstones composing the phosphorite-bearing strata. The experiments carried out make it possible to recommend general technical specifications for the design of a tool for drilling phosphorites.

In the course of experimental drilling, critical values of the axial load were established at which the mechanical penetration rate reaches its maximum values. The obtained axial load values were taken as rational. As a result of the research carried out, a formula suitable for calculating the rational axial load on a cutter bit has been found analytically and verified experimentally.

In the explosion of powerful charges of explosives in a rock mass, zones of vaporization, melting, crushing and cracking are formed. The limiting state of a rock during vaporization and melting is characterized by an entropy characteristic, which does not depend on the conditions of the experiment. The entropy of vaporization and melting are constants of proportionality in the relations between the energy of vaporization and melting of the rock and the boiling and melting temperature ...

One of the promising directions for the development and improvement of new drilling methods is the destruction of rocks by melting or vaporizing them under conditions of intense thermal influence in the bottom-hole zone. The efficiency of drilling-melting depends little on the hardness and plasticity of rocks, as well as on external factors, and in this sense has a certain universality, which allows already now to foresee its advantages over mechanical drilling in some specific conditions of well sinking ...

Drilling operations at placer deposits are difficult due to the specific structure of placers. Non-cohesion, friability of sandy-pebble deposits, their water content, heterogeneity , the presence of boulders of different sizes complicate drilling in alluvial strata. ...

Significant expansion of diamond drilling has put forward a new area of research related to the study of the nature of diamond drill bits under conditions of high contact temperatures, which are characterized by the destruction of the hardest rocks and drilling with compressed air blowing ...

Lubricating and cooling liquids used in drilling practice can be divided into aqueous solutions of electrolytes (NaCl, CaCl₂, etc.); solutions of surface-active substances – surfactants (soap and oil, sulfanol, OP-7, etc.) and emulsion solutions obtained from special emulsols (B, SNAD-1, ZL-4, etc.), as well as from various oils introduced into the solution together with emulsifying additives and special additives. Emulsion solutions can be of the oil-in-water or water-in-oil type ...

To obtain washing solutions are used clay powders produced by various plants and local lump clays. By the cost of clay material spent on the preparation of 1 m³ of standard solution (with a conventional viscosity of 25 s), as a rule, the wrong conclusion is made about the economic efficiency of local lump clays. Approximate calculations have shown that the replacement of local clays and mixed-composition clay powders used by geological organizations with high-grade clay powders is quite expedient and economically justified.

General remarks about the downhole process under study. A modern diamond impregnated crown can work downhole in two different modes: in perfect and imperfect diamond exposure at the face of the crown. This provision applies not only to impregnated and multilayer crowns, but also to single-layer crowns operating under forced feed ...

When studying ice from the core of Shubina boreholes 250, 75 and 952.5 m drilled respectively at 50 km, 353 km and at Vostok station, two types of air inclusions were identified. The first of them can be traced to a depth of 940 m and owes its origin to loose packing of atmospheric ice crystals in the process of accumulation. In the snow strata, cavities of this type are located between aggregates of converged grains and are filled by atmospheric air ...