RU2019663C1 - Method for drilling blastholes - Google Patents

Abstract

FIELD: mining. SUBSTANCE: method includes feeding of rotating borer to blasthole bottom, breaking of rocks by cutting tool and flushing of blasthole with aqueous solution of sodium or potassium carbonate in concentration of 6-20 mas.%. Novelty consists in use of flushing fluid in form of aqueous solution of alkali metal carbonates ensuring combined destructive thermochemical action on hard sandstones in drilling blastholes. EFFECT: higher drilling rate. 1 dwg

Description

 The invention relates to mining, and more specifically, to methods for accelerating drilling of holes in strong sandstones having a strength of 10 or more on a scale of prof. M.M. Protodyakonova.

 A known method of drilling holes in rocks, including feeding a rotating drill with a cutting tool to drill the hole, breaking the rock with a cutting tool, washing the hole with water to remove drill trifle (1).

 The known method has the following disadvantages. Washing holes with water only contributes to the removal of drilling fines and has virtually no effect on the drilling speed, energy consumption and cutting tool consumption.

 A known method of accelerating the drilling of strong sandstones, including feeding a rotating drill with a cutting tool to cut a hole, breaking up the rock with a cutting tool, washing the hole with aqueous solutions of surfactants (2).

 Surfactants are substances whose molecules or ions in an aqueous solution under the influence of molecular forces are concentrated on the interface between a liquid and a solid. The effect of lowering the hardness of the rocks when using surfactants is based on the expansion of microcracks by active substances that form at the bottom of the well under the influence of rock cutting tools.

 A significant disadvantage of this method is the inability of the surfactant to effectively destroy strong rocks, in particular, strong gerbils, with a strength of 10 or more on the scale of prof. M.M. Protodyakonova, consisting mainly of silicon dioxide.

 In addition, it is known that in the zone of rock destruction by a cutting tool, especially during rotary drilling, the temperature rises due to mechanical friction of the tool along the rock, and under such conditions the surfactant activity decreases due to a decrease in adsorption - (2, p. 168).

 The aim of the proposed method is to increase the drilling speed in hard sandstones while reducing unit costs and cutting tool consumption.

This goal is achieved by the fact that in the known method of drilling holes, including feeding a rotary drill with a cutting tool to bore a hole, destroying the rock with a cutting tool and washing the hole with a liquid, aqueous solutions of alkali metal carbonates NaCO ₃ or K ₂ CO ₃ s are used as the washing liquid concentration of 6-20%.

 As a result, the dissolution of silicon dioxide is achieved, from which strong gerbils mainly consist. As a result, the mechanical strength of strong sandstone is significantly reduced, which ensures a significant increase in drilling speed while reducing specific energy consumption and consumption of cutting tools.

 The essence of the interaction of a solution of alkalis and alkali metal carbonates with sandstone is as follows.

Sandstones as a rock consist mainly of silicon dioxide SiO ₂ , and are sedimentary rock of compacted sand. Sand is quartz grains of SiO ₂ .

SiO _{2 is} practically insoluble in water. Being silicic anhydride, it easily passes into silicate by reaction with alkalis:
SiO ₂ + 2NaOH = Na ₂ SiO ₃ + H ₂ O;
SiO ₂ + 2KOH = K ₂ SiO ₃ + H ₂ O; (alkali metal silicates are soluble in water).

;
SiO₂ + K₂CO₃ = K₂SiO₃ + CO

;
Аморфный диоксид кремния можно легко перевести в раствор при взаимодействии с растворами NaOH, KOH, NaCO₃, K₂CO₃; при этом образуются растворимые в воде силикаты щелочных металлов (Реми Г. Курс неорганической химии, том 1, М., 1963, с. 534. Изд. иностр. лит. пер. с немецкого, XI издания).Similarly, SiO ₂ reacts with a reaction with alkali metal carbonates:
SiO ₂ + Na ₂ CO ₃ = Na ₂ SiO ₃ + CO

;
SiO ₂ + K ₂ CO ₃ = K ₂ SiO ₃ + CO

;
Amorphous silicon dioxide can easily be converted into solution by interaction with solutions of NaOH, KOH, NaCO ₃ , K ₂ CO ₃ ; in this case, water-soluble silicates of alkali metals are formed (Remy G. Course of Inorganic Chemistry, Volume 1, Moscow, 1963, p. 534. Ed. foreign literary translation from German, XI edition).

It has been established and proposed that the simultaneous complex effect of the temperature factor (during mechanical drilling) significantly enhances the chemical effect of alkali metal carbonates Na ₂ CO ₃ or K ₂ CO ₃ with a concentration of 6-20%, which does not discredit the novelty of the proposed method.

 The strong sandstone weakened in this way is easily destroyed by the tool and washed out of the hole.

 The laws of chemical kinetics - the law of mass action (Geldberg, Vaage) and Vant-Hoff rule - state that the rate of a chemical reaction increases with an increase in the concentration of reacting substances (Nekrasov V.V. Course in General Chemistry. M., 1954, p. 121 - 129) .

 Based on experimental studies conducted at the Stakhanov branch of KSMI, the following dependence of the required solution concentration on the strength of sandstone was established.

 A comparative analysis of the proposed method with the prototype shows that the proposed method differs from the known one in that more active (in comparison with the prototype) aqueous solutions of alkali metal carbonates with a concentration of 6-20% are used as washing liquid for holes. At the same time, higher concentrations are used for stronger sandstones and, if necessary, a significant increase in the drilling speed.

 In addition, in contrast to the prototype, where the applied solution has only a physical effect on the rock, in the proposed method, the proposed solution has an active complex thermochemical effect on the rock.

 Thus, the proposed method meets the criterion of "novelty." Since the proposed method is characterized by new features and a new set of features, namely, the new chemical composition of the washing liquid, its new concentration, as well as increased activity on sandstone due to complex thermochemical interaction, this ensures the achievement of a new cumulative effect - an increase in drilling speed when at the same time reducing energy consumption and consumption of cutting crowns. Therefore, the proposed method meets the criterion of "significant differences".

 Comparison of the proposed solution not only with the prototype, but also with other technical solutions in this and related fields of technology did not reveal the signs that distinguish the proposed solution from the prototype, which allows us to conclude that the criterion of "significant differences" is met.

 The drawing shows one of the possible devices by which the proposed method can be implemented.

 A device for implementing the proposed method consists of a drill 1 with a cutting tool 2, a drilling machine 3, for example, a core drill or pneumatic drill, a coupling 4 on the drill 1 for supplying a washing solution through a channel in the drill to the bottom face 5 of a hole 6, a pump 7 for forcing a washing a solution from a tank 8, an irrigation pipe 9 for supplying water and a tank 10 for a solution of alkali metal carbonates. A flexible hose 11 is used to supply the solution from the pump 7 to the coupling 4 of the drill 1.

The device operates as follows. The required concentration of the washing solution is created in the tank, pouring the required volumes of water, alkali metal carbonates Na ₂ CO ₃ or K ₂ CO ₃ into the tank 8, respectively, from the pipeline 9 and the tank 10. The amount of water and alkali to be filled is determined using simple flow meters (not shown).

 After creating the necessary concentration in the tank 8, turn on the pump 7, through which the flushing solution is supplied through a flexible hose 11 to the drill channel 1 through the side coupling 4. From the drill channel 1, the solution enters the bottom 5 of the hole 6, where it thermochemically interacts with the rock, mostly strong sandstone, softening it. Chemically softened rock is easily destroyed by a cutting tool 2, which is informed of rotational-translational movement from the drilling machine 2. Drilling fines are washed out of the borehole 6 with a solution. The spent solution drains by gravity along the groove on the soil of production into the sump (not shown). After sedimentation of rock fines from the settler, the solution can again be supplied to the tank 8 for reuse, or may be delivered to the surface.

Using the proposed method for accelerating the drilling of strong sandstones provides the following advantages compared to significant methods:
1. Increasing the speed of preparatory workings by reducing the time for drilling holes.

 2. Improving the productivity of drillers, because with softened rock, less often it is necessary to change the cutting tool due to which the coefficient of machine time increases.

 3. Reduced energy and tool consumption.

An experimental verification of the proposed method was carried out at the mine. Menzhinsky PA "Pervomaiskugol" during the passage of field drift on the mountains. 1047 m, with a sandstone strength factor of 11 on the M. M. Protodyakonov scale. The use of a 9% aqueous solution of Na ₂ CO ₃ or K ₂ CO ₃ during drilling allowed to reduce the drilling time of 78 holes (full cycle) from one and a half shifts (9 hours) to one shift (6 hours).

Claims (1)

METHOD FOR DRILLING HOLES, including feeding a rotating drill with a cutting tool to drill a hole, destroying the rock with a cutting tool and flushing the hole with liquid, characterized in that, in order to increase the drilling speed in hard sandstones while reducing specific costs and cutting tool consumption, as a flushing tool liquids use aqueous solutions of alkali metal carbonates Na ₂ CO ₃ or K ₂ CO ₃ with a concentration of 6 - 20%.

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