CH<sub>4</sub> and CO<sub>2</sub> monitoring in the air of underground coal mines in southern Brazil and GHG emission estimation

Bonetti, Beatriz; Abruzzi, Rafael Colombo; Peglow, Carolina Pereira; Pires, Marçal Jose Rodrigues; Gomes, Cleber José Baldoni

doi:10.1590/0370-44672018720105

Acessibilidade / Reportar erro

Brasil

REM - International Engineering Journal

Español English

Brasil

Español English

sumário « anterior atual seguinte »

Sumário

Mining • REM, Int. Eng. J. 72 (4) • Oct-Dec 2019 • https://doi.org/10.1590/0370-44672018720105 copy

CH₄ and CO₂ monitoring in the air of underground coal mines in southern Brazil and GHG emission estimation

Authorship SCIMAGO INSTITUTIONS RANKINGS

Abstract

This study aims to assess methane (CH₄) and carbon dioxide (CO₂) concentrations in the ventilation systems of two coal mines (A and B) in the Santa Catarina coal deposit in southern Brazil (Paraná Basin, Bonito Formation), and estimate their greenhouse gas (GHG) emissions. The highest CH₄ levels (1.8%) were recorded in strong methane emanation areas in mine A, below the lower explosive limit (5%). The IPCC-recommended methods significantly overestimated the methane emission (up to 80%) when compared to the experimental data measured for each mine. Application of an alternative method made it possible to estimate direct CO₂ emissions, indicating that CO₂ accounted for 22 to 77% of total GHG emissions. Carbon dioxide emissions are generally not included in GHG emission inventories, indicating that the coal industry underestimates the contribution of this gas. As such, it is recommended that the methodology used for these calculations be revised and that specific emission factors be applied for each mine. In order to improve the accuracy of inventories, more sampling needs to be carried out in all operational and abandoned mines.

keywords:
underground coal mines; emissions; greenhouse gases

Sampling Sites	Mine A						Mine B
	CH₄ (ppm)			CO₂ (ppm)			CH₄ (ppm)			CO₂ (ppm)
1^st Campaign/2014
Mine entry	<4^a a Limit of Detection (LOD) of CH4;			849	±	28	<4^a a Limit of Detection (LOD) of CH4;			718	±	21
Ventilation Circuit	117	±	1	1,194	±	8	96	±	17	1,661	±	21
	143	±	21	1,226	±	2	51	±	4	1,626	±	19
Emanation Areas	18,006	±	865	6,086	±	207
Ventilation Outlet	213	±	10	1,624	±	25	54			1,748
2^nd Campaign/2015
Mine entry	<4 ^a a Limit of Detection (LOD) of CH4;			793	±	100	<4^a a Limit of Detection (LOD) of CH4;			756	±	100
After detonation	669	±	100	1,913	±	365
Emanation Areas	3,523	±	69	1,339	±	25
	1,137	±	332	1,691	±	200
Ventilation Outlet	143	±	2	1,256	±	947	34	±	3	1,295	±	168
3^rd Campaign/2016
Mine entry	<4 ^a a Limit of Detection (LOD) of CH4;			751	±	52	<4^a a Limit of Detection (LOD) of CH4;			741	±	203
Ventilation Outlet	110	±	41	1,012	±	117	26	±	0	1,375	±	16
4^th Campaign/2016
Mine entry	<4 ^a a Limit of Detection (LOD) of CH4;			992	±	168	<4 ^a a Limit of Detection (LOD) of CH4;			894	±	117
Ventilation Outlet	338	±	146	1,565	±	174	13	±	3	1,346	±	143
Security Limits
NR15 or NR22^b b CO2 workplace tolerance limit (NR15, 2014) and CH4 tolerance limit (NR 22, 2018) in Brazil;	1%			3,900			1%			3,900
MSHA TLV^c c Threshold Limit Values (TLV) by Mine Safety and Health Administration (MSHA, 2001) in the United States;	n.a.^d d Not allowed.			5,000			n.a.^d d Not allowed.			5,000

Mine	Methodology	Gas	Unit	Emission
Mine	Methodology	Gas	Unit	Min.	%	Max.	%
A	Method M1 (Tier 1)	CH₄	t CH₄ year^-1	3,984		3,984
	Method M2 (Tier 3)	CH₄	t CH₄ year^-1	755		798
	Method M3	CH₄	t CH₄ year^-1	104		487
		CH₄^a a Methane emission estimated by method M3 was converted in CO2-equivalent unit using CH4 GWP of 21 (IPCC, 2006).	t CO_2eq year^-1	2,184	78	10,227	67
		CO₂	t CO₂ year^-1	626	22	5,133	33
	Total GHG emission		t CO_2eq year^-1	2,810	100	15,360	100
B	Method M1 (Tier 1)	CH₄	t CH₄ year^-1	6,432		6,432
	Method M2 (Tier 3)	CH₄	t CH₄ year^-1	377		1,120
	Method M3	CH₄	t CH₄ year^-1	28		56
		CH₄^a a Methane emission estimated by method M3 was converted in CO2-equivalent unit using CH4 GWP of 21 (IPCC, 2006).	t CO_2eq year^-1	588	30	1,185	23
		CO₂	t CO₂ year^-1	1,390	70	4,037	77
	Total GHG emission		t CO_2eq year^-1	1,978	100	5,222	100

Country	Mine	Estimation method	[CH₄] in VAM		Methane Emission		EF calculated	Reference
			range	average	Methane Emission		EF calculated
			%	%	t CH₄ year^-1	million m³ year^-1	(m³ t^-1)
Brazil	Mine A	Tier 1			3,984	0.6	10	This study
		Tier 3		0.05	755-798	1.15 - 1.21
		Alternative	0.01 - 0.03	0.02	104-487	0.15 - 0.73	0.40-1.22
	Mine B	Tier 1			6,432	9.8	10
		Tier 3		0.05	377 - 1,120	0.57 - 1.70
		Alternative	0.0013 - 0.0055	0.0034	28 - 56	0.03 - 0.08	0.03 - 0.09
India	Moonidih	Alternative	0.1 - 0.2	0.15	6,342	9.4	6.3-12.6	Harpalani, 2009HARPALANI, S., PRUSTY, B. K. Quantification of Ventilation Air Methane Emission from Gassy Underground Coal Mines in India. Washington, USA: Environmental Protection Agency (USEPA), 2009.
	Sudamdih	Alternative	0.02 - 0.04	0.03	740	1.10	0,74 - 1.48
	Low gassy mines	Tier 1	<0.1		431,000	634	10	Singh, 2016SINGH, A. K., KUMAR, J. Fugitive Methane emissions from Indian Coal Mining and handling activities: estimates, mitigation and opportunities for its utilization to generate clean energy. Energy Procedia, v. 90, p. 336-348, 2016.
	(Degree I)	Alternative	<0.1		100,000	149	2.91
China	Mine Region D.1	Alternative	0.06 - 0.1	0.07	5,427	8.1	0.8	Su, 2011SU, S. et alii. Fugitive coal mine methane emissions at five mining areas in China. Atmospheric Environment, v. 45, n. 13, p. 2220-2232, 2011.
China	Mine Region D.2	Alternative	0.06 - 0.12	0.09	4,754	7.1	0.7
South Africa	Koornfontein	Alternative	0.04		5,310	7.9	0.70	Lloyd & Cook, 2005LLOYD, P. J. D., COOK, A. Methane release from South African coalmines. Journal of the South African Institute of Mining and Metallurgy, v. 105, n. 7, p. 483-490, 2005.
	Twistdraai		0.01		1,716	2.6	1.01
	Matla		0.01		1,092	1.6	0.41
	Douglas		0.005		446	0.7	0.07
	New Denmark		0.01		301	0.4	0.27
	Boschmans		0.002		89	0.1	0.01

Fundação Gorceix Rua Carlos Walter Marinho Campos, 56, Cep: 35400-000, Tel: (31) 3551-4730 - Ouro Preto - MG - Brazil
E-mail: editor@rem.com.br

Acompanhe os números deste periódico no seu leitor de RSS

[1] 3 beatriz.bonetti@acad.pucrs.br

Brasil

Brasil

CH4 and CO2 monitoring in the air of underground coal mines in southern Brazil and GHG emission estimation

Abstract

CH₄ and CO₂ monitoring in the air of underground coal mines in southern Brazil and GHG emission estimation