Optimized Ventilation Model for Polymetallic Mines in Peru

Optimized Ventilation Model to Improve
Operations in Polymetallic Mines in Peru
Vladimir Flores , Luis Arauzo , Juan Jara and Carlos Raymundo
Abstract Currently, deficient ventilation systems are a frequently observed problem
in mining. Such deficient ventilation systems lead to the recirculation of stale air or
air with toxic gases. This translates into an increase in the costs of ventilation and
electrical consumption for the mining organizations as conventional and practical
solutions simply include options such as buying a greater number of fans. Moreover,
this problem also exposes the mine workers to an unsafe work environment with
unfavorable conditions that could end in minor, incapacitating, or fatal accidents.
Therefore, this research seeks to optimize ventilation systems by introducing the
Ventsim software tool to develop efficient coverage, addressing, flow, circuit or net-
work characterization, and air balancing in conjunction with avoiding the stagnation
of toxic gases in underground work. The primary result of the proposed model’s
application in this study was the reduction in ventilation costs related to electricity
consumption.
Keywords Underground mining ·Ventilation system ·VENTSIM software ·
Optimization
V. F l o r e s ( B)·L. Arauzo ·J. Jara
Escuela de Ingeniería de Gestión Minera, Universidad Peruana de Ciencas Aplicadas (UPC),
Lima, Peru
e-mail: [email protected]
L. Arauzo
e-mail: [email protected]
J. Jara
e-mail: [email protected]
C. Raymundo
Dirección de Investigación, Universidad Peruana de Ciencas Aplicadas (UPC), Lima, Peru
e-mail: [email protected]
© Springer Nature Switzerland AG 2019
Y. Iano et al. (eds.), Proceedings of the 4th Brazilian Technology
Symposium (BTSym’18), Smart Innovation, Systems and Technologies 140,
https://doi.org/10.1007/978-3-030-16053-1_50
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1 Introduction
Currently, the mining sector has become one of the most important industries in
Peru. However, the Peruvian Ministry of Energy and Mines [1] reported 13 fatal
accidents due to gassing and poisoning in underground work environments from
2000 to 2018, which is equivalent to 5% of the total number of accidents in the said
period. Therefore, mining organizations currently consider that, for the development
of operations activities, minimum working conditions must be guaranteed within
their work. Although mining operations include water pumping, hydraulic filling,
compressed air, electric power, and ventilation as part of the general services pro-
vided to mining sites, several mining companies focus their efforts on guaranteeing
adequate underground ventilation. According to Supreme Decree 024-2016-EM [2],
the main purpose of mine ventilation is to supply the amount of clean air required by
the number of workers, the equipment used, wood consumption, high temperatures,
and dilution of gases and leaks, to guarantee favorable heat-environmental conditions
for the workers, and, consequently, favorable conditions for ore extraction from the
mine to the surface. To this end, as the depth at which underground work is conducted
deepens every day, mining companies require new or better ventilation systems that
may comply with the application criteria of the Peruvian mining regulations.
This paper proposes a ventilation model optimized through the Ventsim tool to
prevent stale air recirculation and reduce mining ventilation costs. This research
study is divided into six Sections: Sect. 2contains the state of the art regarding the
research topic; Sect. 3covers the development of the proposed model; the validation
of the results is presented in Sect. 4. Finally, Sects. 5and 6 present the discussion
and conclusion respectively.
2 State of the Art
Mechanized ventilation in underground mining means using ducts and auxiliary fans
to transport air flows from the surface to the work inside the mine, for which fresh air
supply and stale air evacuation circuits are also used [3]. Because this ventilation is
forced, it works differently from natural ventilation. There are three types of forced
ventilation: vacuum, in which polluted air is sucked from the front through the duct
owing to the depression created by fans located at both end points [4]; pressure,
which is characterized by the fact that air enters the front of the bottom through the
pipe, is driven by fans, and displaces the mass of stale air into the main air stream
through the gallery [5]; and the third type is called the “balanced” type, in which
both of the abovementioned types are used [6].
In recent years, the first mechanical fans, known as centrifugal fans, were built.
These fans offer high static pressure and medium flow and can work at high speeds
with their efficiency ranging from 60 to 80% [7]. Next, the first axial flow fans were
developed, which are the most commonly used fans today. These fans offer higher air

Optimized Ventilation Model to Improve … 517
flow as their efficiency ranges between 70 and 80%, and they are capable of working
at the highest possible speeds. Noticing the most outstanding differences between
the two types of mechanized fans, axial fans produce high noise levels; they are also
versatile and cheap. In contrast, centrifuge fans produce less noise and are rigid but
much more expensive.
Information technologies serve as support to elaborate and develop an adequate
ventilation system plan. Among them, South African software leads the ventilation
system improvement market owing to its characteristics. In the studies conducted
by Suvar et al. [5], it is evident that using Visual Advanced Ventsim provides solid
three-dimensional (3D)-graphics or precise ventilation system layouts for the detailed
analysis of the given mining network. Furthermore, this software is an extremely use-
ful tool for technicians, and it fundamentally demonstrates that any type of ventilation
network may be modeled, simulated and solved, regardless of its complexity.
Therefore, according to the studies performed by Jing and Cheng [8] in the Maji-
agou coal mine using the Ventsim software, with air strength being used as the study
parameter, the consumption of electric power was reduced almost in half in all venti-
lation branches. In addition, the authors argue that Ventsim may not only be used for
ventilation network calculations, simulations, and air flow dynamics but may also be
used to help in short and long term ventilation system planning. Finally, the study
performed by Chambergo [3] shows a way to reduce energy costs in the ventilation
system, emphasizing that this may directly or negatively affect mine production.
3 Contribution
Ventilation designs are based on the Hardy Cross theory, which is a method of suc-
cessive approximations that determines the flow running through each pipeline and
its direction. This theory is based on Kirchhoff’s laws for the conservation of energy
and charges in electrical circuits. In this manner, the model proposed herein supports
the analysis of the characteristics and behavior of existing ventilation systems [9].
Furthermore, based on the review of previous research studies wherein scenarios are
presented in which the use of software in industrial companies has been productive,
software implementation in mining planning areas may solve different issues that
the mining sector currently faces. Therefore, this study proposes a ventilation design
optimization model for an underground mining company.
The methodology focuses on the key exploitation process, which covers mine
ventilation. The model presents three components: mine analysis, tests, and com-
putational simulation together with benefits and indicators (Fig. 1). In this manner,
the management of ventilation systems in underground mines is comprehensive as it
combines advanced computational simulation tools with theoretical and experimen-
tal analysis.

518 V. Flores et al.
Fig. 1 Flow chart for the optimization of an underground ventilation system
4 Validity
Compañia Minera Condestable (CMC) S.A. owns and operates its Mina Condestable
and Mina Raúl underground operations near the town of Mala, Department of Lima,
Peru. This organization commercializes copper concentrates as its main product,
with concentrations of gold and silver.
4.1 Compañia Minera Condestable (CMC) Mine Analysis
Total Operation Flow CMC employs a total of 408 workers within the mine and
the ratio per worker, according to the regulations, is 3/m3of air. Thus, the work crew
air requirements (QTr) are 1224 m3/min. Further, CMC has 94 pieces of equipment
within the mine, which total 10,755 HP. Therefore, the equipment air requirements
(Qeq) are 32,264 m3/min.
As CMC does not use wood in its operations processes, in this particular case,
a zero-flow due to wood consumption (QMa) was considered. With respect to the
flow required owing to work temperatures (Qte), a minimum speed of 6.7 m/min was
found in the mine (Table 1). The average work area was 16 m2and the number of
levels in which the temperature exceeds 23 °C was five. The levels that presented high
temperatures were NV.-350, NV.-460, NV.-490, NV.-520, and NV.-550. Therefore,
the flow required by high temperatures is 536 m3/min.
The flow rate required to dilute the gases produced by blasting (Qexp) is approx-
imately 7265.25 m3/min (Table 2).

Optimized Ventilation Model to Improve … 519
Tabl e 1 Air requirements due to high temperatures
QTe 536 m3/min
Vm 6.7 m/min
A16 m2
N 5 Levels
Tabl e 2 Air Requirement due to Consumption of Explosives
Method Explosive Area (m2) Air speed
(m/s)
No. of levels
D.S_024_2016_EM ANFO 15 25 17
Emulsion 15 20 2
Novitsky ANFO and emulsion
Tabl e 3 Flow required
owing to leaks QFu 5103.6 m3/min
Qtr 1224 m3/min
QTe 536 m3/min
Qma 0 m3/min
Qeq 32,264 m3/min
Qexpl 6975 m3/min
Tabl e 4 Total air flow
required for operations QFu 39,127.6 m3/min
Qtr 1224 m3/min
QTe 536 m3/min
Qma 0 m3/min
Qeq 32,264 m3/min
QFu 5103.6 m3/min
As per Table 3, the air flow required owing to leaks (QFu) is equivalent to
5103.6 m3/min.
Then, the air flow required for operations (Table 4) is 39,127.6 m3/min.
Finally, based on the previous analysis, the total air coverage in the mine is 92.07%,
which means that there is a deficit of 7.93% or 3105 m3/min.
General Balance On the one hand, the entry of air into the mine, as recorded by
the stations, was 36,023 m3/min, which is equivalent to 1,265,488 cfm. On the other
hand, the total stale air extracted to the surface is 36,674 m3/min, which is equivalent
to 1,294,945 cfm. Therefore, the balance between air income and air outflow was
102%.
Geometric Study CMC has two Administrative Economic Units: Mina Con-
destable and Mina Raúl. The work dimensions are, mostly, 4 ×4 m. These works are
classified into GL-Galleries, XC-Cruisers, RP-Ramps, PQ-Pits, and CH-Chimneys.