OTHER
ATMOSPHERIC
EMISSIONS
Cathode collection at Milpillas
OTHER
ATMOSPHERIC
EMISSIONS
All of Peñoles’ operations have the necessary equipment installed to comply with regulations on the emission of contaminating substances into the atmosphere.
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Most of the company’s emissions can be attributed to its metallurgical processes for producing zinc and lead; we therefore monitor the presence of sulfur dioxide and lead particles in the air continuously and in real time using an automated high-tech network to make sure that we remain in line with official standards to not inconvenience the neighboring community.
Lead concentrations in ambient air must not exceed 1.5 µg/m3 in a rolling three-month average, which is the limit established by current public health regulations.
We control sulfur dioxide (SO2) emissions to meet our own internal criteria, which are even stricter than the limits ordered by the Mexican Environmental Protection Agency (Profepa). In fact, we maintain levels well below the maximum permissible limits in ambient air quality for this pollutant. As of February 15, 2020: 0.11 ppm on average for 24 hours, and 0.025 pm on average for one year. Emissions limits were tightened on February 16: the limit for one hour is now 0.075 ppm (196.5 µg/m³), calculated as the arithmetic average of the 99th percentiles of the last three consecutive years, obtained from the daily highs, and the 24-hour limit must be 0.04 ppm (104.8 µg/m³) calculated as the maximum of three consecutive years, obtained from 24-hour averages.
Controlling emissions to comply with these stricter standards has been a complex task, because instead of emitting sulfur dioxide—one of the world’s most critical contaminants—generated in the lead and zinc smelting process, we use it to produce sulfuric acid, oleum, ammonium bismuth, liquid sulfur dioxide and ammonium sulfate as fertilizer.
426,287 t
of sulfuric acid in our facilities during the year, which can capture and process emissions and transform them into end products.
Our own internal criteria for SO2 emissions are even stricter than the limits ordered by the authorities.
90-DAY MOVING AVERAGE LEAD CONCENTRATION IN AMBIENT AIR (μg/m3)
METALÚRGICA MET-MEX, 1999-2020
2.5
2.0
1.5
1.0
0.5
0
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
90-day moving average
Official Mexican Standard.
Note: Maximum permissible three-month average (NOM-026-SSA1-1993)= 1.5 ug/m3
AVERAGE DAILY CONCENTRATION OF SO2 (ppm)
IN AMBIENT AIR AT METALÚRGICA MET-MEX
0.15
0.12
0.09
0.06
0.03
0
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
Daily average
Official Mexican Standard.
Note: Maximum permissible daily limit (NOM-022-SSA1-1993)= 0.13 (until March 2011).As of February 16, 2020, 24-hour limit must be 0.04 ppm.
Final filtering, wastewater treatment plant, Met-Mex
In addition to optimizing our use of sulfur dioxide, we have an emergency plan under which our productive processes can be partially or fully shut down if weather conditions prevent the atmosphere from properly dispersing the pollutants emitted. This helps us avoid surpassing the above-mentioned limits and polluting the air.
We have the facilities necessary to capture and process—meaning monetize—our emission of these pollutants, so that instead of releasing them into the air we transform them into end products. For example, instead of issuing almost 400,000 metric tons of sulfur dioxide into the atmosphere, we produce 426,287 metric tons of sulfuric acid, 11,218 metric tons of oleum, 27,336 of liquid sulfur dioxide and 180,027 of ammonium sulfate (fertilizer).
Most of the emissions generated in our chemical plants are particles, which are captured by dust collectors. And although our mining units do not generate significant atmospheric emissions, they apply measures for containing emissions of flyaway dust, such as keeping tailings dams and roads watered and planted. All ore sample analysis labs in the mines, in addition to the electrolysis plant at Milpillas, have dust collectors and gas cleaners.
Working at furnace smelter, Met-Mex
As of February 16, 2020, SO2 concentration limits in ambient air tightened, from a 24-hour average of 0.11 ppm to 0.04 ppm.
In this 2020 Report we present the sustainability performance of the operations of Peñoles and the generation of shared value with the groups of interest.
