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Basic Technical Commonly tested

Mine Portal Backfill

noun

Pronunciation: /maɪn ˈpɔrtəl ˈbækfɪl/

The controlled placement of compacted fill material, such as rock fragments or processed tailings, into abandoned mine entrances to prevent unauthorized access and stabilize surrounding rock. Portal backfilling reduces public safety hazards, prevents rainwater infiltration into mine workings, and isolates subsurface voids from surface disturbance.

Plain English

Filling the entrance opening of an abandoned mine with compacted material to seal and stabilize it.

Etymology & History

Origin languageEnglish
Rootmine (from Old French mine) + portal (from Old French, gateway) + backfill (from back + fill, Middle English)
First recorded use1950s
Usage frequencyCommon

Usage

"The reclamation contractor completed mine portal backfill at three abandoned shaft entrances to eliminate trespassing hazards and prevent water infiltration."

Style guide notes: Distinguish portal backfill from complete portal closure; specify backfill material specifications and compaction requirements.

Also known as

entrance backfilling shaft sealing portal closure material

Contrasted with

portal opening entrance exposure

Related Terms

Frequently Asked Questions

What materials are suitable for mine portal backfill?

Compacted coarse aggregate, large rock fragments, processed ore, and clay-rich materials provide structural support and water resistance.

Why is portal backfill required in mine reclamation?

It prevents unauthorized access, eliminates falling hazards, reduces water infiltration, and stabilizes surrounding rock from surface disturbance.

Why Test Candidates on This?

Relevant for junior-level professionals understanding basic mine closure and public safety procedures.

Required skill level: Junior

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