Brackish water in unsaturated confining beds at a Texas lignite mine

Journal Article · · Ground Water; (United States)

OSTI ID:6320773

Dutton, A R

Deposits of low permeability are hydrologic barriers between reclaimed land and juxtaposed aquifers and should limit the impact of mining on ground-water quality. Claystone and mudstone in argillaceous facies of the Calvert Bluff Formation (lower Eocene, Wilcox Group) function as confining beds in the East Texas Basin. In the subsurface and at the outcrop, water in argillaceous deposits is brackish to saline. Samples of vadose water from the outcrop of confining beds at the Big Brown lignite mine in Freestone County, Texas, have a chloride concentration of up to 3500 mg/l and total dissolved solids of up to 8000 mg/l. Groundwater composition evolved from Eocene sea water by seven- to nine-fold dilution with rain water. Ion exchange, pyrite oxidation, and calcite dissolution further modified water composition. The amount of recharge through the vadose zone where confining layers crop out is probably negligible over an extremely long time. Meteoric flushing in reclaimed land at the surface mine is many times greater than that in unmined mudstone deposits, and the chemical composition of vadose water in reclaimed land is changed by further dilution and water-rock reactions. 31 references, 8 figures, 4 tables.

• Research Organization: Texas Univ., Austin
• OSTI ID: 6320773
• Journal Information: Ground Water; (United States), Journal Name: Ground Water; (United States) Vol. 23:1; ISSN GROWB
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010900* -- Coal
Lignite
& Peat-- Environmental Aspects
ALKALINE EARTH METAL COMPOUNDS
AQUIFERS
BROWN COAL
CALCITE
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONACEOUS MATERIALS
CARBONATE MINERALS
CARBONATES
CENOZOIC ERA
CHALCOGENIDES
CHEMICAL COMPOSITION
CHLORINE
COAL
COAL DEPOSITS
COAL MINING
CONTAMINATION
ELEMENTS
ENERGY SOURCES
ENVIRONMENTAL EFFECTS
ENVIRONMENTAL QUALITY
FEDERAL REGION VI
FOSSIL FUELS
FUELS
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
GROUND WATER
HALOGENS
HYDROGEN COMPOUNDS
IRON COMPOUNDS
IRON SULFIDES
LAND RECLAMATION
LIGNITE
MATERIALS
MINERAL RESOURCES
MINERALS
MINING
NONMETALS
NORTH AMERICA
OXYGEN COMPOUNDS
PERMEABILITY
PYRITE
RESOURCES
SULFIDE MINERALS
SULFIDES
SULFUR COMPOUNDS
SURFACE MINING
TERTIARY PERIOD
TEXAS
TRANSITION ELEMENT COMPOUNDS
USA
WATER
WATER QUALITY