Anoxic Limestone Drain
nounPronunciation: /ænˈɒksɪk ˈlaɪmˌstəʊn dreɪn/
A passive treatment system consisting of a subsurface channel filled with limestone that treats acidic mine drainage in the absence of oxygen. The limestone neutralizes acid while the anoxic conditions prevent rapid oxidation of iron and precipitation, allowing greater contaminant removal efficiency.
Plain English
An oxygen-free underground limestone channel that neutralizes acid in mine drainage while preventing iron from clogging the system.
Etymology & History
Usage
"The coal mine's anoxic limestone drain successfully neutralized acidic seepage before it reached surface water while maintaining subsurface conditions."
Style guide notes: Write 'Anoxic Limestone Drain' with capitals; use 'ALD' abbreviation only after first full mention in same document.
Also known as
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Related Terms
Frequently Asked Questions
Why must anoxic limestone drains operate without oxygen?
Anoxic conditions prevent iron oxidation and precipitation that would clog the system, allowing limestone longer contact time to neutralize acid and higher treatment efficiency.
What is the typical lifespan of an anoxic limestone drain?
Well-designed ALDs can function for 20-50+ years depending on acid loading rates, limestone quality, and whether the system becomes saturated with iron compounds.
Why Test Candidates on This?
ALD design, operation, and performance are frequently assessed in mine reclamation certifications focusing on passive treatment technology competency.
Required skill level: Mid