Prevention and safety plans are a priority to combat eventualities in mines.
Mining companies have the obligation to adequately manage ventilation system during mining operations. The aim is to provide a working atmosphere where the necessary air circulates to preserve health of workers. Manuel Martínez, a specialist of The Chamber of Mines of Peru comments on the emergency and risk management plan in mines.
The specialist of The Chamber of Mines of Peru says that toxic gases are the most relevant contaminants in operations because they come from the development of the mining work itself. For example, the use of explosives in blasting and the combustion of diesel equipment.
In addition, another contaminating agent is dust, depending on its particle size and composition. In addition, depending on its concentration and exposure time, it can be considered health risk to workers. This is because the respiratory system is susceptible to airborne contaminants.
According to the specialist, Manuel Martínez, «it is necessary to establish adequate ventilation and to establish the use of personal protection elements. It is also necessary pre-occupational examinations in accordance with works to be performed; periodic medical checkup for workers exposed to contaminants, as well as relocation and rotation of personnel to avoid overexposure. All this evaluated and controlled by an emergency and risk management plan».
Likewise, for mining companies, the injection and distribution of fresh air inside the tunnels are important factors, as well as the extraction of exhaust air, which is one of the most relevant challenges of underground operations. For this reason, The Chamber of Mines of Peru promotes training of mining companies to optimize the emergency and risk management plan.
In 2014, as part of its emergency and risk management plan, the Chilean company Codelco announced the installation of an intelligent ventilation system in the new level of the El Teniente Mine. This mechanism injects and distributes fresh air directly to the areas that need it, at the time and quantity required. This creates a more efficient management of this problem and a considerable reduction in energy costs. Similar experiences in underground deposits in Canada show potential savings from 30% to 40% in energy consumption in this aspect.
Mining ventilation is so important that the corresponding authorities in each country establish the legal framework that aims to configure a favorable working environment.
For example, in Peru, Supreme Decree of 2010 establishes that the development of the activity shall be kept within the occupational exposure limits for chemical agents. It also states that before entering the work area, toxic gas measurements are taken. These are recorded and communicated to the workers. In case of mechanical or electrical failure of fans, the extractive work must be stopped and its access must be closed until the quantity and quality of the air go back to normal conditions.
Likewise, in Chile, regulations applied are Supreme Decree 594 of the Ministry of Health (last modified in 2015), which establishes a limit of 40 ppm for the presence of carbon monoxide. In addition, a value of 2.4 ppm is established for nitrogen dioxide and the ambient oxygen concentration in the work area must be between 19.5% and 21%.
In the case of Ecuador, two documents can be mentioned: Supreme Decree on Mining Safety (enacted in 1996) and the Regulations on Occupational Safety and Health in the Mining Sector (drafted in 2014). Both regulations establish that the emergency and risk management plan in all underground operations must consider ventilation circuits, being of natural or mechanical origin, in order to maintain a permanent supply of fresh air that favor circulation and exit of exhaust air.
Colombian legislation (decree 1886, issued on 09/21/2015) regulates critical issues such as mandatory training for miners, the need and importance of using personal protective equipment, as well as maintenance of electrical installations, ventilation and dust control. Also, obligations are established for the mining project holder, including permanent inspections and continuous monitoring of the mine condition to avoid any accident; in addition to ensuring uninterrupted measurements of methane, carbon monoxide, hydrogen sulfide and other contaminants. These must be observed before starting works and during workers’ exposure to these substances.
In underground operations, several types of contingencies may occur. One of the most important is fire, mainly because of the dimensions these events can reach and the number of workers that may be involved. Other emergencies include vehicle entrapment, gas intoxication, landslides and other situations that occur less frequently, such as electric shock and falls to a different level.
To avoid these types of situations, it is necessary for companies to make the necessary efforts to provide a safer working environment. One of the main measures is the development of an emergency plan. This plan is automatically activated when a contingency is notified and lies in a structured and trained communication management. This will ensure the movement of workers, with the respective safety equipment. This program is specific to each of the deposits, because each mine has its own unique characteristics.
The emergency and risk management plan must consider that in the case of a small deposit, it is necessary that workers who are trapped have the necessary breathing devices. In the case of a very large mine, it is imperative to have shelters.
Finally, in the case of an intermediate size mine, configuration of the deposit must be assessed. The objective in each situation is to have adequate personal protective equipment and well marked and active shelters in order to avoid as many casualties as possible.
