Production of drilling
tools for surface
and underground drilling

Machine-Building Holding JSC (hereinafter referred to as MH JSC) is the only manufacturer in
the Russian Federation that produces all elements of drilling strings for pneumatic impact
drilling under high pressure compressed air. The main elements of drill strings for pneumatic
impact drilling are damping adapters; top adapters; drill rods; centering bushings; bottom
adapters; hammers; drill bits.
MH JSC specialists have extensive experience in production and implementation of drilling
tools, and are constantly working to modify designs and expand the range of products. Over the
past three years, the product line of drill rods for surface mining and damping adapters has
been significantly extended.
All the products have passed pilot tests and are put into series production. To master the serial
production, the necessary metal-cutting, welding, heat treatment equipment, as well as special
ultrasonic testing devices for the metal science laboratory were purchased and put into
operation.
These products are successfully used at many mining enterprises in the Russian Federation, the
CIS and in the countries of the African continent.
Drill rods are used to transmit sufficient torque and load to the drill bit (cone bit) in order to
establish the optimal rate of penetration without compromising the service life of rock
destruction tools (hereinafter referred to as RDT).
Using rigid and straight alloy steel pipes is one of the best ways to eliminate drill string sagging
and borehole deviation. During the production of boreholes, the drill rod is subjected to intense
abrasive wear due to the sandblasting effect created by the rapid rise of drill cuttings and slurry
through the annular space and significant alternating axial loads. Thus, in the production of drill
rods, it is important to use pipes and threaded elements (nipples, couplings) made from quality
high-alloy steel grades, and the production shall be carried out in compliance with all
technological conditions, especially thermal and chemical-thermal operations.
Correctly selected and high-quality drill rods primarily have a positive effect on:
— reduction of the drilling rig wear,
— transfer of energy from the rotator to the RDT,
— RDT centering in a borehole,
— RDT life extension,
— reduction of friction when the string passes through the drill table,
— stabilization of borehole walls to prevent their collapse,
— reduction of drilling costs,
— drilling precision for more efficient drilling and blasting operations,
— improving the final fragmentation of blasted rock.
It is recommended to install a damping adapter on the very top of the drill string, between the
rotator and the drill rod. The damping adapter is a pneumatic mechanism designed to dampen
vibration loads and connect the drill string to the rotator of the drilling rig.
The advantages of using a damping adapter are as follows:
— better monitoring of the torque,
— absorption of harmful vibrations,
— drilling speed increase,
— prolonged service life of drilling rig elements,
— increasing RDT service life.
While introducing these products into series production and receiving feedback from
consumers at all stages of pilot testing, information was obtained and analyzed, which made it possible to significantly improve the product performance. The MH JSC specialists carried out
research work with further implementation of a number of progressive solutions to increase
the durability of drill rods and damping adapters.
Currently, metallurgical companies in the Russian Federation have a wide range of materials to
produce parts for mining engineering, but the correct selection of steels for manufacture of drill
rods and damping adapters plays a significant role in further performance characteristics. The
materials for these products shall withstand the influence of abrasive wear and have sufficient
viscosity. MH JSC, together with Russian metallurgical companies, conducts research work to
improve the physical and mechanical properties of the steels used. It also conducts
experiments to create new special grades of steel that have no analogues in the Russian
Federation and abroad.
MH JSC designers and technologists declare increased requirements for the strength and wear
resistance of manufactured products. The achieved requirements became possible thanks to
modern equipment for thermal and chemical-thermal processing of metals. The Company's
scientific and production staff select the necessary technological modes of heat treatment.
Optimal heating and cooling modes are established thanks to our own modern laboratory
engaged into study and research of the structure and properties of materials.
MH JSC pays special attention to ensuring high quality products, establishing control at all
stages of the production process, starting with quality control of the raw materials used, and
ending with determining the compliance of the released duct with design documentation. The
use of the updated fleet of high-precision metal processing machine tools significantly
increased the requirements for the parts manufacture, which in turn affects much the
performance criteria of the products released. Checking the quality of parts at all stages of
production has become a major part of the production process at MH JSC.
As a result of the modern development of engineering knowledge of personnel and new
production technologies at MH JSC, the quality of drill rods and damping adapters is at a fairly
high level, not inferior to the world's leading analogues, which is successfully confirmed by their
application at many mining enterprises in Russia and abroad.
The MH JSC specialists take a responsible approach to pilot testing of drill rods and damping
adapters. Thanks to accumulated invaluable experience and correct comparability of the
information received, the production process is accelerated, which in turn is a kind of progress
engine for further development of MH JSC in the field of creating reliable and high-performance
drill rods and damping adapters.
Having all the drilling string elements at hand, MH JSC specialists can offer mining enterprises a
unique opportunity for cooperation — concluding a meter-by-meter contract, in which the
client pays only for the actual linear meters drilled. Our specialists also offer optimal conditions
for service and warranty maintenance of the entire range of used drilling tools produced by MH
JSC.

Around the world, mining companies are paying special attention to replenishment and exploration of reserves of mineral deposits.
Geological research and its technological assets play a special role in this issue. One of the most important elements in geological research and exploration of all types of minerals is experimental drilling. Modern economic reality dictates more and more stringent requirements for carrying out geological exploration work — increasing volumes, reducing costs and time of work. Until recently, one of the most used geological exploration methods was core drilling, the so-called sampling of core columns. Core drilling is a type of high-speed drilling in which rock destruction occurs in a ring, and not over the entire face area. The interior of the rock is formed and preserved as a column of undisturbed core structure. The core is periodically jammed to be separated from the bottom and raised to the surface. The main decrease in productivity during the core drilling process occurs during additional operations for disassembling and assembling the drill string and lifting the core receiver for sampling, which take considerable time.
Today, the reverse circulation drilling method, or RC drilling, is gaining increasing popularity. The economic efficiency and productivity of this method is significantly higher than core drilling. The point is that mineral deposits (ore, mineral, etc.) most often have an irregular shape, far from any geometric figure. The dimensions of deposits in regard to strike lines and slant vary from several tens to hundreds of meters, and individual deposits can extend up to several kilometers. The reserves of one ore body can range from a thousand to a million tons, and sometimes exceed billions of tons, which shall be analyzed during deposit development in order to make a correct assessment of economic efficiency.
All this led to the search and development of a more effective sampling method compared to core (diamond) drilling. The search and development of a new method began in the 1970s in Australia. In 1972, the reverse circulation method was developed for rotary drilling, the principle of which was to use double drill rods. By the end of 1980, this method had proven itself to be more productive and cost-effective compared to core drilling.
In 1980, RC drilling allowed Western Australia to significantly increase its mineral production.
The development of technology and the desire to improve the reverse circulation method to enhance the quality of samples led to creation of the first hammer for RC drilling in 1990. The same year, the technology of air hammer drilling with reverse circulation was supplemented with the application of high pressure air compressors, which led to even greater productivity and increased penetration rates. All this has made it possible to significantly increase the efficiency of geological exploration, and as a result, RC drilling has become one of the most economical and accurate drilling methods in prospecting surveys.
Reverse circulation sampling (RC drilling) is a type of drilling that uses compressed air to effectively obtain drilled rock from a well through the internal area of the tool used for the purpose of further collection of samples. The reverse circulation method is full-hole drilling without unnecessary auxiliary operations. The reverse circulation method is implemented by installing a drive shroud after the drill bit in the operational drilling part, which forms an enclosed work area. In this area there is created a differential pressure that is converted into aerodynamic lift force. This force lifts the cuttings up through the internal tubes located inside each rod.
The double beam rods consist of the outer and inner tubes. The use if the inner tube allows to divide the drill rod into two enclosed areas (tube routes). The intertube area (between the outer and inner tube) provides a continuous flow of high pressure compressed air from the compressor to the RC hammer. During drilling crushed rock is brought to the surface via the inner tube to collect samples.
The use of high-pressure compressors makes it possible to achieve not only high productivity of RC drilling, but also to obtain the effect of preliminary drying of undrilled rock mass in the working area in front of the drill bit. Air in the working area, where differential pressure is created, penetrates into fractures and pores, displacing water. Pre-dried and drilled rock immediately flows from the drill bit through inner tubes, first to the deflector, and then through sampling hoses to the cyclone and then to the divider, where it is directly collected into sampling bags. This sampling layout does not provide cross-contamination from the external drilled medium. The use of quality equipment, tools and skilled operators produces sampling results that rival the accuracy of the core method. Under With RC drilling, samples can remain dry even several hundred meters below the groundwater level. Dry samples are preferable as they are more accurately digested for subsequent analysis. The initial stage of sample preparation for chemical analysis during core drilling begins with grinding the sample (core) into pieces approximately 10–20 mm in size. RC drilling does not require this procedure, which significantly speeds up the process of obtaining data on mineral content.
The speed of drilling with reverse circulation is comparable to the speed of drilling with air hammers using high pressure compressed air, used mainly for blasting and technological wells, and at great depths it can even exceed it. The productivity of drilled meters per day ranges from 150 to 300 m, which is many times higher than core drilling. Reverse circulation drilling is applied not only for surface deposits (pits),, but also for mines. One of the goals of RC drilling method is providing operational information on the content of mineral resources in a particular site. High drilling productivity allows you to quickly collect samples and send them for evaluation, which in turn gives a clear picture of the distribution of the boundaries of ore bodies with an empty hole. Less time for processing and proper distribution of activities help reduce overall costs. Currently, RC drilling is the most productive and economical method for extracting rock samples. Until recently, drilling tools for RC drilling were presented only by foreign companies. The experience accumulated in the manufacture of mining equipment together with the experimental work held allowed Machine-Building Holding JSC, Yekaterinburg (MH JSC) to launch into production a whole range of drilling tools for RC drilling, which can be found on the company’s website.

V.V. Lyukhanov, Director of Machine-Building Holding JSC,
S.B. Alferov, Sales Director of Machine-Building Holding JSC
The uniqueness of the manufacturing technology of all MH JSC drilling tools lies in the fact that
all processes are systematized and organized using traditional and modern production
management methods. These methods are built in such a way that the influence of the human
factor on the quality of products is minimized. This conclusion was made based on the results
of repeated research and testing of products, including in the conditions of mining enterprises.
For more than 10 years, specialists from Machine-Building Holding JSC (Ekaterinburg) have
been successfully implementing their own developed program for manufacturing of import-
substituting products for the mining industry. MH JSC developments are mainly aimed at
facilitating the work of miners by enhancing productivity, reducing labor intensity, and also
increasing the service life of equipment. Most of the developments have been brought to
industrial operation and are successfully used at many mining enterprises in Russia and the CIS
countries.
Specialists from Machine-Building Holding JSC have mastered the technology of manufacturing
drill round bits for mechanized drilling with threaded connections R32, R35 and R38 of nominal
diameters 43, 45 and 51 mm. The main difficulties in implementing the project were connected
with coordination and approval of the relevant technological regulations in the working groups
of the enterprise and organization of cooperation with MH JSC adjacent and internal structural
divisions.
Housings for drill round bits are manufactured from high-alloy steel grades produced by Russian
metallurgical plants under special agreements that strictly regulate the tolerance for non-
metallic inclusions and harmful impurities. MH JSC employees additionally carry out the
incoming inspection of the steel supplied. It should be noted that for a long time it was believed
that domestic metallurgical enterprises were not capable of producing such steels for
significant alternating loads, and this problem was one of the limiting factors in the
development of many products in various sectors of domestic industry. After numerous
meetings and negotiations, the specialists of MH JSC managed to find mutual understanding
with the employees of metallurgical enterprises and agree on the regulations for the
production and acceptance of the necessary steels.
Machine tool builders developed various technical solutions for re-equipping existing machining
centers and acquiring new ones with special capabilities that take into account the specifics of
the technology for manufacturing drill round bits. For example, machining centers were
equipped with special bar loaders that made it possible to load bars for the entire work shift
with no operator engaged. The main requirement of MH JSC technologists for the processing
equipment was to arrange the possibility of turning the housings of drill round bits with
minimum amount of parts reinstallation. For this, machining centers with the special
configuration for the foundation and the spindle were introduced. This configuration allows to
process parts by turning, milling and drilling operations without removing them from the
machine. Machining centers were also equipped with the additional movable chuck, which,
after processing one side of the part in the stationary chuck without operator intervention, was
able to re-fix the product for processing the other side, etc.
Tool makers equipped machining centers with special cutting fixtures, which allowed to provide
the necessary processing accuracy and performance. MH JSC implements the mechanical
processing of drill round bits housings with the use of modern, high-precision and high-
technology equipment. Heat treatment is carried out using special modes that are developed,
approved and adjusted based on repeated laboratory metallographic studies, as well as the
results of numerous pilot and industrial tests.
Drill round bits housings manufactured by MH JSC are reinforced with carbide inserts with
increased wear resistance. MH JSC specialists select the optimally required configuration of drill
round bits housings as well as carbide tools for them for various mining, geological and
technical conditions.
In addition to manufacturing drill round bits, MH JSC specialists, according to numerous
requests from mining enterprises, managed to master the production of consumables
(couplings and shanks) for foreign hammer drills, the quality of which is significantly superior to
their imported counterparts. Consumables for imported hammer drills manufactured by MH
JSC are the optimal alternative for mining enterprises as part of import substitution. Currently,
measures are being taken to expand the production to increase the quantity and range of these
products.
The uniqueness of the manufacturing technology of all MH JSC drilling tools lies in the fact that
all processes are systematized and organized using traditional and modern production
management methods. These methods are built in such a way that the influence of the human
factor on the quality of products is minimized. This conclusion was made based on the results
of repeated research and testing of products, including in the conditions of mining enterprises.
The first tests of drill round bits KNSH 43-R32.BSр MH711.00 of nominal diameter 43 mm
(10 pcs.), KNSH 45-R32.BSр MH712.00 of nominal diameter 45 mm (10 pcs.) and coupling Т-38
MH780.00 (5 pcs.) manufactured by MH JSC were performed by “Shchit-Stroy” Company
(Ekaterinburg), which provides contracting services for tunneling works at mining enterprises in
the Sverdlovsk region. Similar drill round bits from a Japanese manufacturer and couplings from
a Swedish manufacturer were taken for comparison. The test results were recorded. Based on
the test results, the commission of specialists from “Shchit-Stroy” Company determined that
drill round bits and couplings produced by MH JSC showed higher durability than products from
foreign manufacturers: drill round bits KNSH 43-R32.BSр MH711.00 and KNSH 45-R32.BSр
MH712.00 – by 31 and 38%, respectively; couplings T-38 MH780.00 – by 30%.
Subsequently, industrial tests of drill round bits were carried out at many mining enterprises in
Russia and other CIS countries. The results are fixed in the test reports. All test results show
that the use of drill round bits produced by MH JSC is more effective than the use of similar
samples from foreign manufacturers.

In conditions of high competition in mineral commodity markets of ferrous and non-ferrous metals domestic mining enterprises are constantly taking measures to reduce costs for mining. A high share of costs is made up of expenses for imported drilling tools and spare parts for imported equipment due to a significant increase in the exchange rate of foreign currencies.
Under these conditions, mining enterprises are pursuing an active policy of import substitution to improve the efficiency of spending funds and increase the competitiveness of finished products. Mining enterprises act as a demanding customer and set tasks for domestic manufacturers to produce reliable, highly efficient mining equipment that is not inferior to imported analogues.

Machine-Building Holding JSC (hereinafter referred to as MH JSC) from Yekaterinburg has been implementing this task since 2009 by manufacturing drilling tools equal in quality and reliability to the best world’s manufacturers of such type of equipment. Over the past 10 years, more than 30 large enterprises in Russia, Kazakhstan, Ukraine, Uzbekistan, Kyrgyzstan and other neighboring countries have chosen MH JSC as the main supplier of drilling tools for high quality and timely deliveries. At the same time, there is a constantly growing high interest in the drilling tools of MH JSC from mining companies from far abroad, mainly from the African continent: Angola, South Africa, Zambia and other countries.
Industrial tests carried out in these countries have shown the high efficiency of using drilling equipment produced by MH JSC in comparison with previously used analogues from foreign manufacturers. Since 2015, along with the production of hydraulic hammer drill bits, specialists of MH JSC launched the production of drill string elements, namely connection couplings and shanks for hydraulic rock drills for production and tunneling. To develop these types of products, a comprehensive modernization of several metalworking shops, the heat treatment shop, and the metal science laboratory was carried out, as well as the necessary equipment was purchased and design documentation was developed. The production shops of the enterprise developed and mastered the relevant technological processes and trained the personnel.
We have mastered the production of shanks and couplings for all major models of hydraulic rock drills. The quality of the shanks and couplings manufactured by MH JSC is confirmed by numerous tests, and the key to the stable quality is the serial production of shanks and couplings for 5 years. Shanks and couplings confidently compete with foreign manufacturers in the market of hydraulic rock drilling tools.
In 2017, we started manufacturing of hydraulic rock drill rods for production drilling. This was preceded by a complex process of coordinating steels and pipe sizes with metallurgical enterprises. One of the mechanical sections and the thermal shop were modernized. Once again, the necessary equipment was purchased, design documentation was developed; The production shops developed and mastered the relevant technological processes and trained the personnel.

Today, MH JSC specialists have mastered the serial production of the entire line of hydraulic hammer drill rods for underground mining with threaded connections R32, T38, T45, T51, ST58, ST68 with a length of 915, 1220, 1525,1830 mm.

In the process of developing the market for hydraulic rock drill rods, a significant demand for fishing tools (taps, bells) was identified, since the ability to eliminate emergency situations when the drill string jams in difficult mining and geological conditions and extract the string from the well can significantly reduce the cost of hydraulic rock drill rods. In this regard, MH JSC specialists developed and mastered the production of the entire line of fishing tools for each standard size of hydraulic rock drill rods.

In the process of testing and industrial application of hydraulic rock drill rods produced by MH JSC, specialists from mining enterprises noted their high performance characteristics, such as:

• high resistance to distortion,

• no malfunction of rod elements,

• wear resistance of threaded connections,

• easy disassembling of the drill string.

In 2019, we launched the production of rods for tunneling. As part of the project, technical requirements for hollow hexagons are being coordinated with metallurgical enterprises. The Company's specialists carry out painstaking preparatory work for the next stage of production modernization: selection and acquisition of machining equipment, equipment for the heat treatment shop, and straightening equipment. As soon as the preparatory work for production modernization is finished and all the technological processes are mastered, we will implement the pilot and industrial tests for the tunneling rods under conditions of mining enterprises. The industrial application of tunneling rods manufactured by MH JSC at domestic mining enterprises will make it possible to implement the last missing element in production chain for hydraulic rock drill strings. This will make it possible to carry out complex deliveries of the entire list of drilling tools (shanks, couplings, rods, bits) for tunneling machines.
When mastering these technologies, the MH JSC specialists had to significantly improve their professional competencies, such as:

• determination of critical loads under various operating modes of shanks, couplings and rods,

• study of mechanical properties and selection of various steel grades,

• coordination of Technical Requirements for steels with metallurgical enterprises

• ensuring high pipe accuracy (quality of outer and inner surfaces, wall thickness, eccentricity),

• preparation of the technical process for processing parts to achieve the required accuracy and surface quality,

• selection of friction welding modes,

• selection of heat treatment modes to ensure high strength and wear resistance of products,

• building a quality control system at all stages of production using the latest measuring instruments,
• testing of rods, couplings and shanks in various mining and geological conditions.

Along with large mining companies, MH JSC actively cooperates with organizations that provide contracting services for drilling and blasting operations. These companies are actively involved in the process of selecting the most efficient mining equipment, test and commission new samples of drilling tools together with MH JSC specialists. We attribute such an active position of our partners primarily to their maximum interest in obtaining positive results from joint work.
Many mining enterprises and contracting companies have already been able to appreciate the advantages of working with the equipment manufactured by MH JSC, such as:
• high level of service,
• qualified technical support,
• consistently high quality of equipment and tools,
• short lead times for introducing new products into series production.

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