December 18, 2015
As a part of ongoing efforts to improve air quality and reduce dust in the Andacollo region, senior management from Carmen de Andacollo, representatives from Chile’s Ministry of Environment and municipal government officials announced the launch of the operation’s detailed Atmospheric Decontamination Plan.
The initiative’s key objective is to lower dust emissions by 65% over the next two years. The changes will come as the result of both new government regulatory requirements and voluntary measures established by Carmen de Andacollo (CDA), including double-layer blasting, a procedure endorsed by the Servicio Nacional de Geología y Minería (Chile’s National Geology and Mining Service).
“As an operation, we are always looking for ways to innovate, with the goal of minimizing emissions. We have come so far, and we will continue to remain focused on continuously improving our environmental performance,” said Manuel Novoa, General Manager, CDA.
What is blasting and how does it create dust?
Blasting is used to fracture rock, giving access to mineral deposits. It is an essential part of the open pit mining process, but the noise and dust created by blasting has the potential to impact surrounding communities.
While most dust settles in and around the mining area, some of it can disperse before settling, carried off the mine site by winds created by weather conditions and other activities on site, such as driving.
What is double-layer blasting?
This innovative new process adopted at CDA uses a technique whereby charges on two different benches of the mine pit are detonated within seconds of each other. Perforations are loaded at 21 metre increments, twice the height of conventional blasting, and incorporate special detonators. Once the top layer has fractured in the blast, it adds to the energy in the lower layer as it goes off.
What are the benefits of the new approach to blasting?
This technique allows for greater control of particle emissions and reduced vibration and noise from blasting. It also significantly reduces the overall particulate matter (PM10) tonnes generated by the operation.
What have been the results so far?
Analysis to date has shown that compared to conventional blasting, for the same concentration and tonnage, double-layer blasting provides a 33% reduction in the amount of PM10 emissions. Research has also shown that this percentage reduction could reach 65% if the technique is incorporated into just half of future production plans.
Is there any cost reduction associated with doublelayer blasting?
Compared to a traditional blast, this technique removes more material per blast because the higher loading releases more energy, which means that less blasting is required.