RU2465460C2 - Development method of diamond-bearing kimberlite pipes - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: after the deposit is stripped, extraction field is separated into a mesh with rhombic cells with sides and a short diagonal, which are equal to diameter of the main well. First, service wells with diameter of not less than 93-112 mm are drilled in mesh nodes as centres; then, the main wells of large diameter are drilled concentrically to service well; core is pulled off the rock mass, lifted to the surface and removed from core barrel. After that, cores of large diameter are supplied to concentration plant and washed out with high-head hydraulic guns, and the pulp formed after excess water overflows from sediment trap is supplied to concentrating devices used during drag extraction of diamonds. After diamonds are extracted, shanks are dehydrated on centrifuges and supplied with the elevator to the warehouse from where they are taken for laying of drilled wells.

EFFECT: avoiding uncontrollable losses of diamonds during extraction, and reduction of formation of new mechanical defects on diamond crystals at kimberlite disintegration.

3 cl, 2 dwg

Description

The invention relates to the mining industry, namely to the open development of kimberlite diamondiferous pipes. The present invention can be used to develop diamondiferous kimberlite pipes in the winter conditions of the North and in more climatically temperate latitudes.

A known method of underground mining by drilling cylindrical workings [1]. The essence of the method is the sinking from the upper borehole floor of a pilot well with a diameter of 250-300 mm to the height of the floor. In its lower part, on the delivery horizon, an expander (up to 3-5 m) is attached to the drill stand and the well is drilled back to the design dimensions in reverse. After practicing the camera, it is filled with a hardening tab. The disadvantage of this method is the need for underground mining for various purposes. In addition, when using this method when developing a diamond deposit, the entire volume of mined kimberlite is destroyed mechanically, which leads to an increase in damage to diamond crystals.

There is a method of developing mineral deposits by drilling large diameter core, which can be carried out by various devices for drilling large diameter wells using a core method, for example, a mechanical core drill used to implement a core separation method [2]. In this case, at first, in the usual way, an auxiliary borehole of small diameter is passed, then a device for core removal is introduced into this borehole, and at the same time, a borehole of large diameter passes through a core drill. Core detachment is carried out by supplying drilling fluid under high pressure, but when the rocks are strong, the fluid pressure is increased by the action of explosives.

The through hole on the axis of the core has the advantage that various devices for tearing the core can be placed in the cavity of this hole, and if the core cannot be torn off by the device from the inside or in any other way, then it is possible to additionally act by any known method or device outside the core by placing a specific device in the annular cavity of a large diameter well. But the main advantage is that diamonds remain intact in the volume of large diameter kimberlite core. However, during further processing in crushers and mills, according to many experts, 18% of large-class crystals receive mechanical damage in the form of cracks, punctures and chips.

The closest in technical essence and the achieved effect is a method for the development of diamondiferous kimberlite pipes according to Russian patent No. 2312989 [3].

In this method, the development of kimberlite and the extraction of diamonds is carried out by successive reciprocating movements of the hydraulic mining unit of a floating dredger throughout the ore body, and the diamond-containing pulp is fed to a floating processing plant, where diamonds are extracted by sequentially performed pulp disintegration operations, particle classification on screens, abrasion of particles in a planetary mill, separation of particles by size in a multi-sieve screen and extraction of diamonds into ore picking tables and in X-ray luminescent separators, and tailings are disposed of by dehydration by centrifugation and storage for subsequent use in laying cavity drilled wells.

All the main operations of this method, such as decompression of the rock mass, rock delivery to the mining installation, its lifting, separation and transportation to the alluvial map, are carried out using water and air without the presence of mechanisms, machines and people in the face. But the main advantage of this method is the high degree of preservation of diamond crystals both in the process of extraction and in the extraction of diamond. However, in the conditions of cold and long winters it is difficult to provide reciprocating movement of the hydraulic mining unit of a floating dredger over the entire area of the ore body. In addition, due to the higher specific gravity of diamond than the density of kimberlite, uncontrolled losses of diamond crystals are possible during the reciprocating movement of the hydraulic mining device. It should also be noted that kimberlite is eroded in the absence of visual and instrument control, and water can be supplied in large quantities to where everything is already blurry, and not enough, where it is poorly eroded. This leads to increased energy consumption for rising water, and also does not exclude the possibility of leaving an uncontrolled pillar that will remain at the bottom of the excavation field. Based on the foregoing, the following tasks can be set:

- effective work of the development method throughout the year in cold and long winters with a high probability of diamond preservation both during mining and in the beneficiation process;

- the exclusion of uncontrolled losses of diamond during its production.

These tasks can be solved when developing diamond deposits in the form of tubes by a method that includes the extraction of kimberlite by successively drilling large diameter kimberlite cores over the entire ore body area, washing the cores hydraulically at the processing plant, sequentially performed pulp disintegration operations, screening particles classification, abrasion particles in a planetary mill, the separation of particles by size in a multi-sieve screen and the extraction of diamonds on picking and lapping tables and in X-ray luminescent separators, and the disposal of tails is carried out by using drilled wells as a material for laying.

In our opinion, due to such performance of the method operations, year-round development of the deposit is achieved in the conditions of the cold North, elimination of diamond losses during their extraction, and also after the kimberlite is washed out, the ratio of solid to liquid pulp is suitable for pumping by ground pumps.

To implement the proposed development method, various methods and devices can be used for drilling pits, large diameter wells, mine shafts or drilling stone columns for buildings. Many of these devices require a cylindrical cavity in the center of the core. Therefore, it is advisable to drill an auxiliary well with a diameter of at least 93-112 mm before drilling the main well in its center. For example, by A.S. USSR No. 67474, a core breaker is introduced into this well, and at the same time, a large-diameter well passes through a core drill. Core detachment is carried out by supplying drilling fluid under high pressure, but when the rocks are strong, the fluid pressure is increased by the action of explosives. But it must be borne in mind that this method places increased demands on the verticality and straightness of the axis of the auxiliary well, since the latter serves as a guide when drilling the main well. Therefore, when drilling auxiliary wells take additional measures to set the vertical axis of the wells and prevent their curvature. Core drilling of an auxiliary well allows the drilling mode and type of device for detaching large diameter core to be identified by core and drilling process.

However, if it is not possible to tear the core from the array in this way, you can use various sawing devices, well expanders, heating devices, hydraulic fracturing, thermal stresses during heating, and even the energy of microexplosions. In this case, the presence of a cavity in the center of the core serves as the channel of energy transfer with which the separation force and the torsion moment, developed by the drilling rig to break the core, will be added. If this is not enough, it is necessary to raise the core pipe and place in the well cavity devices that implement various methods of separating the core from the array. The simultaneous action of destructive forces inside and outside the core makes it possible to break off a kimberlite core with a diameter of 1 m or more. If there are cracks crossing or core fractures in the borehole section, large diameter core blasting is carried out in the most damaged part of the core, using core grab devices that overlap the core section.

Well curvature is mainly caused by uneven rock resistance to fracture, and the curvature occurs in the direction where the fracture resistance is least. Therefore, by artificially creating the necessary resistance and limiting the care of the tool, it is possible to keep the curvature of the well within acceptable limits. Such conditions are created when drilling adjoining and overlapping wells. For such wells, it is possible to manufacture a device for parallel drilling, for example, according to A.S. USSR No. 374451. Using this device, the drilling of wells is carried out by a conductor, which is placed in a previously drilled main well.

However, it should be emphasized that when drilling large-diameter wells, well curvature when drilling shallow wells in relatively uniform rocks is less likely. As a means of reducing curvature, it is possible to consider laying a drilled well with empty rock after enrichment or overburden rocks before drilling an adjacent well.

The core raised upward in the absence of a year-round road can be washed out on the territory of the rig and fed through the pipeline to the processing plant. In winter, core samples are brought to an enrichment plant, where they are destroyed by a high-pressure water jet of hydraulic monitors. At the same time, by changing the diameter of the nozzle, the pressure of the supplied water and the distance from the nozzle to the core, it is possible to regulate the water supply necessary for destruction. The resulting pulp, as in the prototype, is fed to sequentially performed pulp disintegration operations, particle screening, particle abrasion in a planetary mill, particle size separation in a multi-sieve screen, and diamond extraction on picking tables and in X-ray fluorescence separators, and tailings disposal carried out by using as a material for laying drilled wells.

The core can be washed out not only by hydraulic monitors, it can be given rotation around its own axis and washed out by hydraulic nozzles mounted on top with the ability to move to the core as it erodes. Due to the rotation of the core and the multi-point pattern of low-pressure high-pressure nozzles, a significant reduction in water consumption can be achieved.

Below, the essence of the proposed method for the development of diamondiferous kimberlite pipes is explained by an example of its implementation with reference to the accompanying drawings. Figure 1 shows a diagram of the drilling of auxiliary and main wells; figure 2 shows the block diagram of the processing plant.

The method is as follows. After overburden of the field, the excavation field is divided into a grid with rhombic cells with sides and a short diagonal equal to the diameter (D) of the main well 1 of large diameter (Fig. 1). In the nodes of the cells, the auxiliary well 2 is first drilled with a continuous face 2 with a diameter of at least 93-112 mm. If the section is complex and represented by fractured and kimberlites of different strengths, then the well is drilled with core extraction, according to which rational drilling regimes of the main well are taken, the place and the device for core breakdown of large diameter, and then, as in the guide, the main well of large diameter is drilled concentrically auxiliary 2 one.

After reaching the intended drilling depth, the core is torn off, and the core pipe with the core is lifted up, where it is placed in a special place equipped with means for extracting the core. The next core is drilled in the same way, and so on, until the planned drilling depth is reached. If the well has no deviation from verticality, then it is laid with a mixture of sand and gangue after enrichment and overburden 3. If the well deviates from verticality, as described above, use a conductor to drill parallel wells, for example, as USSR No. 374451. The extracted core is sent to the beneficiation plant, where it is first washed with hydraulic monitors 4 with the possibility of manual movement in all directions or, alternatively, high-pressure hydro-jet nozzles (Fig. 2). In the latter case, the core is rotated around the axis, and the nozzles, as the core is eroded, moving, maintain the optimal distance to the core for erosion. The pulp is sent to the settling tank 5, from where the excess water returns to the hydromonitors, and the pulp with the required T: G ratio is sent to the first disintegrator 6. The mixture disintegrated by it is fed to a two-sieve screen 7, where it is divided into two fractions with particle sizes from 1.6 to 50 mm and less than 1.6 mm. From the oversize space of the screen 7, the fraction allocated by it enters the second disintegrator 8, where the fraction is re-disintegrated. From the disintegrator 8, the mixture enters a screen 9, which predominantly emits a fraction of less than 1.6 mm, and a fraction larger than 1.6 mm enters the planetary mill 10, where deep abrasion of the material occurs with virtually 100% diamond preservation. From the planetary mill 10, the material enters the multi-sieve screen 11, where the final separation of fractions by size occurs. Fractions with a particle size of 50 to 4 mm go to the picking 12 and lapping tables 13, and fractions with a particle size of 4 to 1.6 mm go to the X-ray luminescent separators 14. On the tables 13 and in the separators 14, 100% of all diamonds coming from pulp to the processing plant.

Fractions separated by screens 7, 9 and 11 with a particle size of less than 1.6 mm form tails, which are dehydrated in centrifuges. Dehydrated tails elevator serves in the tailings warehouse. Thus, almost dry fractions with a particle size of less than 1.6 mm remain in the warehouse, which are taken from the warehouse for laying drilled wells.

The main disadvantages of the prototype in our proposal are eliminated by the fact that the extraction of kimberlite is carried out by drilling core samples of large diameter. In this case, the loss of kimberlite is controlled both visually and by geometric measurement methods. The kimberlite erosion process is also visually controlled and possible paths of loss of diamond crystals can be quickly eliminated. Insignificant destruction of diamond crystals is possible when core is drilled, however, they remain in the entire core volume. During further processing, as in the prototype, high-pressure dynamic action of water jets on diamond crystals and enrichment technology do not destroy large diamond crystals. Thus, the tasks are completely solved by the above proposal without prejudice to the advantages of the prototype.

Information sources

1. Borodin A.A. On the possibility of excavating kimberlite ore by vertical cylindrical workings [Text]. / A.A. Borodin, N.P. Borodin, A.A. Borodin // Actual problems of the development of kimberlite deposits: current status and prospects: Sat. doc. / International scientific-practical conference "Peaceful-2001: July 1-9, 2001 - M., Publishing House" Ore and Metals ", 2002. - S.339-345.

2. A.S. 67474 USSR, Class 5a, 37. Method for core removal after sinking with core drill [Text]. / G.I.Bulakh (USSR). - No. 30-46 (343046); declared 02/19/1946; publ. 12/31/1946, bull. No. - 4 s .; silt.

3. RF patent No. 2312989, IPC E21C 41/26, B03B 7/00. A method for developing diamondiferous kimberlite pipes and a floating installation for its implementation [Text]. / V.G. Kochnev, G.I. Novikov, B.C. Fortygin, V.V. Verzhak, S.A. Vybornov, G.F. Piven, L.V. Oparin, S.V. Solopov; Applicant and patent holder: V.G. Kochnev, G.I. Novikov, B.C. Fortygin, V.V. Verzhak, S.A. Vybornov, G.F. Piven, L.V. Oparin, S.V. Solopov. - No. 2006125390/03; declared 07/14/2006; publ. 12/20/2007, Bull. No. 35 (III). - S.560-561.

Claims (3)

1. A method for the development of diamondiferous kimberlite pipes, including the extraction of kimberlite and its supply to dredge-type enrichment devices in the form of pulp, sequentially performed operations of pulp disintegration, particle classification on screening, abrasion of particles in a planetary mill, particle size separation in a multi-sieve screen and diamond recovery on picking tables and in X-ray luminescent separators, characterized in that the development of the ore body is carried out by sequential drilling of Kim core erlita large diameter over the entire area of the ore body and erosion cores hydraulically at the concentrator, and the recycling is effected by the tails Bookmarks drilled wells. 2. The method of developing diamondiferous kimberlite pipes according to claim 1, characterized in that the cores are rotated around its own axis, and the hydraulic nozzles are mounted on top with the possibility of moving to the core as it erodes. 3. The method of developing diamondiferous kimberlite pipes according to claims 1 and 2, characterized in that the drilling of large diameter cores and drilling of auxiliary wells are carried out on a grid with rhombic cells with sides and a short diagonal equal to the diameter of the main well of large diameter.

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