Skip directly to site content Skip directly to page options Skip directly to A-Z link Skip directly to A-Z link Skip directly to A-Z link


Centers for Disease Control and Prevention. CDC twenty four seven. Saving Lives, Protecting People
Search
            ×
                        Mining
                        Mining
                            NIOSH
                            All CDC
                    Submit
                For a full list of topics:A-Z Index
                Advanced Search
            Advanced Search


The National Institute for Occupational Safety and Health (NIOSH)





Mining Publication: The Modified Direct Method: A Solution for Obtaining Accurate Coal Desorption Measurements
Keywords: Coal Gas measurement instruments Gases Measurement methods
This page is archived for historical purposes and is no longer being maintained or updated. Contact NIOSH Mining if you need an accessible version.
Original creation date: May 2001
Authors: WP Diamond, SJ Schatzel, F Garcia, JP Ulery
Conference Paper - May 2001
Download PDF Document (0.15 MB)
NIOSHTIC2 Number: 20021290
Proc Intl Coalbed Methane Symp, May 14-18, 2001, Tuscaloosa, AL: University of Alabama; :331-342
The direct method test was developed for general mine safety applications by the U.S. Bureau of Mines in the early 1970's to measure the gas content of coal samples obtained from the relatively shallow depths of eastern U.S. coal mines. Over time, applications for gas content data evolved which required increasingly accurate desorption values. It became evident that some of the inherent weaknesses in the original direct method test could best be addressed by abandoning the water displacement based desorbed gas volume measurements. The ideal gas law based modified direct method (MDM) and associated desorbed gas volume measurement apparatus was developed to provide the most accurate desorption values possible for rock samples obtained from any gas-bearing strata. The MOM bas a number of significant advantages, including: (1) increased accuracy, especially for low gas content samples, (2) a test apparatus with an integral sampling port to facilitate the collection of uncontaminated gas samples, (3) an inherent head space effect correction in the periodic MDM desorbed gas volume calculations, (4) measurement of positive and negative desorbed gas volumes, (5) elimination of differential gas solubility effects as a source of error inherent in the water displacement methods, and (6) a compact and rugged test apparatus that along with the elimination of the "glassware" required for the water displacement methods, facilitates its use in the field.
Image of publication The Modified Direct Method: A Solution for Obtaining Accurate Coal Desorption MeasurementsConference Paper - May 2001
Download PDF Document (0.15 MB)
NIOSHTIC2 Number: 20021290
Proc Intl Coalbed Methane Symp, May 14-18, 2001, Tuscaloosa, AL: University of Alabama; :331-342
See Also
The Composition of Coalbed Gas
Diesel Exhaust Aerosol, Review of Measurement Technology
Gas Content Determinations of Salt Samples Using Acoustic Responses
Gas Sorption and Transport in Coals: A Poroelastic Medium Approach
Geology and Gas Content of Coalbeds in Vicinity of Bureau of Mines, Bruceton, Pa.
The Limiting Oxygen Concentration and Flammability Limits of Gases and Gas Mixtures
Measuring the Gas Content of Coal: A Review
Optically Powered Remote Gas Monitor
Rapid (Grab) Sampling During Full-scale Explosions - Microscopic and Analytical Evaluation
Reservoir Engineering Considerations for Coal Seam Degasification and Methane Control in Underground Mines
Page last reviewed: September 21, 2012
Page last updated: September 21, 2012
Content source: National Institute for Occupational Safety and Health, Mining Program
Facebook
        Twitter
        LinkedIn
        Syndicate Mining
        Site BrowserSafety and Health TopicsData & StatisticsMethodologyMine DisastersMSHA Data FilesMine & Mineworker ChartsTools & PublicationsTools You Can UsePublicationsNews & ArticlesResearch ProgramNORA Mining CouncilStrategic PlanMining Program, 2019-2023Miner Health Program, 2020-2030ProjectsContractsFunding OpportunitiesMining LinksAbout UsContact NIOSH MiningEmploymentFacilitiesHistoryVisitor Information NIOSH Homepage
 NIOSH A-Z
Workplace Safety & Health Topics
Publications and Products
Programs


About CDC
					Contact Us
					800-232-4636
 Facebook Twitter Instagram LinkedIn Youtube Pinterest Snapchat
 CONTACT CDC
				Contact Us
							Call 800-232-4636
							Email Us
			ABOUT CDC
				About CDC
							Jobs
							Funding
			POLICIES
				Accessibility
							External Links
							Privacy
							Policies
							No Fear Act
							FOIA
							OIG
							Nondiscrimination
							Vulnerability Disclosure Policy
			CONNECT WITH US
				Facebook
								Twitter
								Instagram
								LinkedIn
							Youtube
								Pinterest
								Snapchat
								Email
			LANGUAGES
				Español
							繁體中文
							Tiếng Việt
							한국어
							Tagalog
							Русский
							العربية
							Kreyòl Ayisyen
							Français
							Polski
							Português
							Italiano
							Deutsch
							日本語
							فارسی
							English


U.S. Department of Health & Human Services
			Accessibility
			External Links
			Privacy
			Policies
			No Fear Act
			FOIA
			Nondiscrimination
			OIG
			Vulnerability Disclosure Policy
			USA.gov


Exit Notification / Disclaimer Policy Close
 Links with this icon  indicate that you are leaving the CDC website. The Centers for Disease Control and Prevention (CDC) cannot attest to the accuracy of a non-federal website.
				Linking to a non-federal website does not constitute an endorsement by CDC or any of its employees of the sponsors or the information and products presented on the website.
				You will be subject to the destination website's privacy policy when you follow the link.
				CDC is not responsible for Section 508 compliance (accessibility) on other federal or private website. Website Disclaimers
 Cancel Continue