The analysis of health and safety deficiencies at [631722]

The analysis of health and safety deficiencies at
work as well as organization, to the surface
mining operations, of useful rocks which can
cause accidents and/or technological failures

Attila Kovacs1*, Sorin Bordoș1, Bogdan Garaliu -Bușoi1, Claudia Miron1, Sorina Stănilă2

1National Institute for Research and Development in Mine Safety and Protection to Explosion –
INSEMEX Petroșani, 32 -34 G -ral Vasile Milea St., 332047 – Petroșani, Hunedoara County, Romania
2University of Petrosani, str. Universitatii 20 , Petrosani, Romania .
Abstract: The exploitation of ore deposits or useful rocks, surface
operations, implies the application of rigorous technologies regarding the
configuration of the operating steps, the safety berms and the slopes, as
well as the acce ss ways to working front. The required measures to carry
out drilling, shooting and evacuation activities involve both issues related
to technological security and safety and health at work for the personnel
involved in these activities, mining establishme nts being required to draw
up appropriate instructions for the situation on the ground, covering both
technological and SSH issues. In some situations, accidents or
technological failures have occurred due to the failure of fully implement
these provisions which, sometimes, have also resulted in human casualties.
The paper aims at presenting 2 case studies to which INCD – INSEMEX
Petrosani carried out technical and scientific expertise for the produced
events.
1 Introduction
Any operation with explosives for civilian use involves risks from the moment of entering
the manufacturing, transporting, storage , loading and performing of the shooting. Given
that explosives are dangerous goods, they can affect both the personnel directly involved in
their use and o ther people not in the security zone. Serious effects on humans as a result of
explosive charges are due either to explosion pressure, throwing of dither material, or to the
stability of structures after shooting such as: slopes, operating steps, or buildi ng demolition
work with explosives . [1, 2, 3 ]
The paper briefly presents two case studies with victims, based on technical and
scientific expertise carried out by INCD -INSEMEX at the request of the authorities. In both
accidents, the victims were people wh o did not directly participate in the blasting activities
but their presence in the work area that was affected by the effects led to these accidents.

* Corresponding author: [anonimizat]

2 Case stud ies
2.1 Technical expertise of the event at the stone quarr y “Dealul l ui Tefic ”
2.1.1 Descrip tion of th e accident place
The objective of technical expertise was to determine the causes that generated the
occurrence of the 14.10.201 1 event at the stone quarry  DEALUL LUI TEFIC”. [2]
2.1.2 Description of the geometric elements of the steps of th e stone quarry
Dealul l ui Tefic” Issacea
The dimensions of the geometric elements of th e steps in the open quarry , i.e. the height of
the steps, the width of the berms and the slope angle, were calculated and adopted in order
to approve the technology ac cording to [2]:
– the geo -morphological structure of the rock-mass in which the step is forme d;
– the physical -mechanical characteristics of the rock s in the step;
– working technology related to the exploitation method;
– functional parameters of the equipment used for the execution of the technological
operations.
The 15m step height adopted wit h the applied technology according to the exploitation
frame method, was correctly set.
Analyzing the field evidences , it is confirmed that the loading and transpo rt activity was
carried out safely.

Fig. 1. Dealul lui Tefic Quarry , Isaccea, Tulcea
By ado pting the long -term exploitation method in Dealul lui Tefic quarry , the following
main requirements are ensured: full occupational safety, high economic efficiency , min i-
mum reserve l osses, field and surface protection, and environmental protection.
Bore drilling and blasting works highlight the following specific parameters:
– height of the step 12 –15 m, the variations being generated by the land unevenness from
the ground;
– 3.5 m burden at a slope angle of 75 -80o;
– the length of the bore holes in diameter of 102 mm, is 14 or 17 m depending on the height
of the tread, achieving a depth of 2 m;
– the distance between th e holes on the same row is 3÷ 4 m and the distance between the
rows 2.6÷3 m.

– number of blast ing holes per cycle are 23, of which 12 on the first row and 11 on the
second row;
– initiating the explosive charge through the NONEL non -electric syst em, with th e use of
millisecon d detonators.

Fig. 2. Geological structure of the slope
Thus, the burden , the distance between the holes in the same row and the rows have the
values specified in the frame method. The explosive charge used to fire the blasting holes
consists of 2 FARE X busters of 450 g, with a base and a m iddle initiation, in the v ecinity of
the buster being 3 L AMBREX cartridges 65mm x3,125 kg at the base, respectively 2
LAMBREX cartridges of the same dimensions at m iddle , as an initiating explosive (fig.3).
The explosive in the column is rep resented by AUSTINI TE (ANFO) weighing 70kg, the
length of the load being 14 m out of the tota l of 17 m – the length of the borehole, the
loading rate of the bore being 75 % of the height of the step, the amount of explosive per
meter of hole the probe bein g between 4.7 – 6 kg/m, the average value being 5.13 kg/m.
On 14.10.201 1, the amount of explo sive was 5.25 kg/m of bore hole , the amount of
explosive per hole – base load – was 70 kg.
Used materials:
– 2 pcs. Booster 450 g;
– 5 pcs. Lambrex 65×3,125 kg;
– 70 kg Austinite;
– Stemming 3 m.

Fig. 3 Loading of t he bore hole

2.1.3 The consequences of the event
Event occurred on October 14, 201 1, at the work point Stone quarry  Dealul lui Tefic” ,
Isaccea, had the followi ng consequences: [2, 3, 4, 5]
– Serious bodily injury of the victim of the S .G. who suffered injuries requir ing healing,
medical care of 70 -80 days, which by their gravity endangered his life and which resulted
in permanent physical infirm ity due to his be ing hit by the resulted material at the quarry
front blasting operation;
– Mild bodily injury in the head ar ea of the second victim B.G. due to the same causes that
did not require hospitalization or special medical care;
– Damage of some equipment in the area where the throwing effect was manifested by the
material resulted during the blasting operation;
– Spreading of the material dredged after the blasting operation outside the security zone
established by the technical documentation, 300 m from where the blasting took place.
2.1.4 Effect of throwing material
Due to the detonation of an explosive charge, besides the desired effec t of d islocation of
the material, unwanted effects (material displacement at large distances, airborne shock and
eventual seismic effects) can occur , that can affect neighboring objectives .
By analogy with the results of works on the properties of explosi ve sub stances, it is
shown that it is quite difficult to calculate the energy of rock fragments produced by a
detonation. [6, 7, 11]
2.1.5 Conclusion of expertise
After the geomorphological analysis, tectonic accidents, cracks/fractures, correlation of the
hourly data and the location of the blasting works and the event occurs , it is retained as a
cause for the occurrence of the event Fly rocks after the blasting operation due to the
presence of previously unidentified crack s/fractures in the front area during dri lling and
loading of the bore holes  [2].

Fig. 4. The throw effect amplification
The presence of such geological anomalies can lead to overloading the front and
modifying the projected parameters (significant decrease of burden ) which can result, after

the shot, in a displacement e ffect of the blasted materi al to considerably larger distances
than those established as safety distances for protection people and goods.
From the data recorded on the file on which the technical expertise was made, there are
no indications tha t there wer e underground c avities in t he front area, which is also
supported by those reported by the staff that carried out and coordinated the blasting.
Also, explosive consumption declared and recorded for this work did not give any clues
to support the overloading of certain hol es due to su ch gaps in the rock-mass.
2.1.6 Influence factors
Amplification of the off -site throw effect due to the use of the shooting technology
described in the frame method, in the a bsence of ident ification of the two major cracks
revealed af ter the occurrence of the event [2, 14] .
Withdrawal of personnel was carried out at the minimum safety distance from the
shooting front, specified in Blasting order no. BEN -21.11/14.10.2011 ” safety and
Instruction s for the use of personal protective equipment and covering in the case of su r-
face blasting , but it was done in the direction of the front, inadvertently, unprotected by the
effects of the detonation .
2.2 Technical expertise of the event at the quarry “Pârâul Cailor ”
2.2.1 Descript ion of the event place
The dolomi tic deposit “Pârâul Cailor ” is situated on the Fundu Moldovei town area , in the
county of Suceava. [1]

Fig. 5. Satellite image of the perimeter of “Pârâul Cailor ” quarry
The exploitation works are c urrently taking place at the level of 11 active stages. The
exploitation method is applied in principle through 5 d ifferent technological variants.
2.2.2 Protecting the rock deposit, land surface and buildings
a) Safety pi llars
The exploitation metho d and the technologies it applies do not create critical are as in the
exploited perimeter of the rock deposit, requiring protection by safety pillars.
b) Managing the mining pressure and stability of the slopes

Due to the programmed exploitation in t he quarry, the geological reserves create
imbalances, both in the plane of the panels and in the whole of the quarry, respectively
between the forces demanding the slopes, the inner strength of the rock, under the direct
action of the various externa l factors (especially technological ones) or internal (struc tural
weakness, fissure, classical tendency), natural (environmental and tension factors such as
the frozen -thawing repetitive effect) or human activities . [2, 3, 4, 5]
Given the fact that the exploitation met hod does not create areas with a breaking trend,
the main el ements of stability of the slopes and berms are constituted by the dimensional
parameters of the steps, established according to the quarry monograph y:
– tread depth angle = 60 -80°;
– quarry pit a ngle = 25 -30°;
– the width of the berm without car transport min. 20 m;
– the width of the berm with car transport min. 30 m;
– the width of the safety berms min. 2 -4 m;
– step height max. 20 m.
2.2.3 The c onsequen ces of event
The event, produced on 10.05. 2014, at the “Pârâul Cailor” quarry , had the following
consequences: [1, 6, 7, 11, 12]
– the sliding of material from the steps no. IV, V, VI, VII, VIII, on the veh icle loading
platform, arranged in the III step;
– death of the I.F. driver and the damaging of the truck .
Much of the energy produced by the explosio n is consumed to induce vibrations
(seismic effect) in the mining massif.
Seismic effects or ground vibrations last longer than d isplacement, breakage, or
proje ction and involve a much large r volume than offset ma tter.
The deposits in the Rarău mountains synclinal have been affected by m ajor transverse
faults that have produced dismantling and displacements of the order of hundreds of meters,
which have generated secondary faults, supporting with much lesser effects than those of
the major tecto nic acc idents.
2.2.4 Conclusion of expertise
After geomorphological analyzes, tectonic accidents, fissures, cracks, correlation of the
hourly data for the execution of the blasting works and the occurrence of the event, it is
retained as a cause for the occur rence of the event, “spontaneous slipping of the rock
bundles from the related fault area of the steps IV, V, VI, VII and VIII in the NE part of the
central axis of the quarry front , due to the low cohesion of the hygroscopic mater ial (clayey
matrix), caus ing the rocks to move down from the above st eps to the operating st ep III”,
where the loading platform of the material exploit ed material by the blasting works was
organized . [1]
Voluntary certification of blasting technology was neede d to ensure seismi cally
protection on basis of m onitoring the seismic effect on blasting.
Revision of Work Security and Safety documentation to provide measures to avoid
similar events. [1]
Conclusions
Performing blasting operations generate a significant ri sk of harm ing the lives and health of
people in the area. Failure to comply with the security instructions, to the extent that they

impose strict obligations, for both execution personnel (trained blasters and other workers )
and the coordinat or of the work may lead to human casualties and / or damage or
destruction of material goods or other unwanted technical events.
The two cases presented in the paper illustrate situations in which overlapping quarry
security measures, insufficie ntly or in correctly esta blished an d applied and their non –
complying by the trained staff in these activities have been overlapped.
Economic operators do not allocate sufficient resources to improve the security and
health measures related to t he blasting activities , in t he sense that the specific working
instructions are not updated when the conditions in the work front change the design of the
blasting operation and the staff is not adequately trained and aware d.
INCD -INSEMEX Petrosani can offer effect ive advice t o improve the safety and health
situation at work and to monitor the effects and blasting parameters.
The program of technical, scientific and research work in which INSEMEX is
concerned and is currently involved , allows t he transfer of u seful inform ation to economic
agents and authorities to limit/ prevent such situations that may result in human casualties or
material damage s.
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