1. Stoichev, Zh., (2009). Loco Drill – Example of Good Collaboration. Minno Delo
i Geologia Journal, No 6-7, 28-30.
Loco Drill – Example of Good Collaboration
A Loco Drill Rig designed especially for horizontal
drilling in underground mine workings has been
in operation since May this year in the Druzhba
Mine operated by the company Lucky Invest AD.
The designer of the machine is Georgi Atanasov,
MEng, an employee of Sandvik Bulgaria EOOD.
The drill rig is compact and small in size which
enables it to be easily moved along the entire
working front of mine galleries with cross
sections between 6-10 square meters, such as
those in the lead-zinc mines in the Rhodopes
mining region.
The Loco Drill Rig is carried on rail tracks,
mounted on a 7 ton locomotive manufactured in
the former Soviet Union. No structural changes
were made to the locomotive during the project
implementation. The loco carries and moves the
drill rig during the advance of the mining
operations, as well as from one work area to
another. All the other machine assemblies with
the exception of the HL300 Hydraulic Drifter
made by Sandvik were manufactured or supplied
by Bulgarian companies. The drill rig is designed
to drill holes with a diameter of 38 mm and a
depth of 2 m at a rate of drilling varying between
1-2 m/min., depending on the rock hardness.
To operate the machine you need three-phase
electricity and water supply. A water flow rate of
approx. 25 l/min. at a pressure between 3-5 bar
is required for normal operation. The machine
will automatically shut down if the water
pressure drops below 1.5 bar.
Operating the Loco Drill
The source of power for the machine’s hydraulic
system is a 30 kW electric motor. One operator
can operate the hydraulic functions using
joysticks, avoiding any physical contact with the
drilling tools, i.e. no operator’s vibration
exposure.
The Loco Drill Rig
operated at the
face in the
Druzhba Mine

2. The entire assembly and finishing works on the
drill rig were done at the Repair Shop on the
company site of Lucky Invest AD, town of Lucky.
The work was commenced in mid-January this
year and the machine was put into operation in
May. Similar equipment has been used in the
South African underground mines and in some
countries of the former Soviet Union. There is no
information about the use of such equipment in
the European Union and on the European
continent as a whole.
Technical and Technological Parameters
One of the bigger advantages of Loco Drill is the
higher performance over the hand-held
Pneumatic Air Rock Drills that are still widely
used by the miners not only in the mines near
Lucky but throughout the entire Rhodopes
mining region. The machine can replace the hard
work of three experienced miners and
significantly boost productivity, provided that
there is a working front. The miners at the lead-
zinc mines are currently using pneumatic rock
drills and need to be physically strong, but in
addition to that the miners are exposed to the
harmful effects of vibrations, dust and noise.
The more important advantages are as follows:
• The prototype operating in the Druzhba
Mine is much cheaper and it is not in any
way inferior to original models,
according to the company's managers;
• The drill rig is convenient and practical
for use in mine galleries with cross
sections between 6-10 square meters,
which is unfeasible for standard
equipment in this category;
• The drill rig is easy to operate; the
operator will quickly learn to use the
controls – usually 3-4 shifts are enough.
• Increased productivity than the previous
method of working;
• The machine has a retractable canopy to
protect the miners, creating a sense of
comfort. When retracted the canopy
does not hinder the movements of the
machine along the galleries;
• The Loco Drill uses electricity and water
to operate, not polluting the
underground mining environment;
• The lighting for the operator is much
stronger.
“Engineer Atanas Marinski has contributed a
lot for the realization of the whole project”,
says Georgi Atanasov from Sandvik Bulgaria
EOOD. “And not only because of the moral
support but mostly because of the risk he
took. Such activity involves considerable
spending for the project implementation -
from the design phase through
implementation and putting in operation.
This risk was actually much greater,
considering that we did the work during a
financial and economic crisis which was felt
more acutely in the mining sector in the
months when we were building and testing
the drill rig.”
Business talks
with Atanas
Marinski, MEng
(in the middle),
Executive
Director, Lucky
Invest AD

3. Engineer Atanas Marinski says: “The idea of
making the drill rig came after hours of
considering how to increase the productivity at
the company and at the same time alleviate the
work of the miners in our mines. Getting a
similar brand new drill rig would be expensive -
it would cost about 300,000 Euro. Therefore, we
started looking for a company that could make a
similar model with as many of the part
components as possible made in Bulgaria, along
with specific requirements for high performance,
easy operation and environmental protection.
We needed such prototype to save the efforts of
seeking assistance from foreign manufacturers
and suppliers.
Moreover, we had not used any hydraulic
machines at our company. Considering all this
we contacted Sandvik Bulgaria EOOD and started
working with their service specialist Georgi
Atanasov. The results are already visible after
several months of work and operation of the
drill rig in the Druzhba Mine. The new prototype
is successful and is in no way inferior to others.
The machine has been contributing to the
improvement of the working conditions for the
miners and does not create any technical,
technological or environmental issues.
Having commissioned the drill rig, we now
comply with the EU requirements for air quality
in underground mines, labor safety, noise
reduction and avoidance of vibrations harmful to
the miners' health. It is well known that these EU
requirements are becoming increasingly
stringent. Moreover, the use of pneumatic
drilling tools (which we are still using) will be
prohibited in the coming years. Further to our
success we intend to continue in this direction
and completely switch to hydraulic machines in
the future.
The making of this drill rig, already tested and
proven at Lucky Invest AD, is an example of
efficient machines made in Bulgaria thanks to
the good will and common efforts of employers
and production companies, contributing to the
improvement of the working conditions in the
mines and development of the Bulgarian mining
sector.”