Advanced Search
Select up to three search categories and corresponding keywords using the fields to the right. Refer to the Help section for more detailed instructions.

Search our Collections & Repository

All these words:

For very narrow results

This exact word or phrase:

When looking for a specific result

Any of these words:

Best used for discovery & interchangable words

None of these words:

Recommended to be used in conjunction with other fields

Language:

Dates

Publication Date Range:

to

Document Data

Title:

Document Type:

Library

Collection:

Series:

People

Author:

Help
Clear All

Query Builder

Query box

Help
Clear All

For additional assistance using the Custom Query please check out our Help Page

i

Effects of stimulation treatments on coalbeds and surrounding strata : evidence from underground observations

Filetype[PDF-3.38 MB]


  • English
    • Details You May Also Like

    Details:

    • Personal Author:
    • Corporate Authors:
      United States. Bureau of Mines.
    • Description:
      "Stimulated vertical boreholes are an effective means of removing gas from coalbeds in advance of mining. This Bureau of Mines report examines the coal mine roof damage potential of stimulation treatments. Twenty-two government-sponsored stimulation treatments have been mined through to determine the effects on the coalbed and roof strata. Vertical fractures in the coalbed were discernible for most treatments, and horizontal fractures were present for about half of the stimulations. Sand-propped vertical fractures were usually short in lateral extent. Evidence of stimulation fluid movement could generally be traced beyond the maximum extent of sand- filled fractures when fluorescent paint was added to the treatment fluids. The maximum lateral extent for a sand-filled vertical fracture was 416 ft, and a paint-coated vertical fracture extended 630 ft. Horizontal fractures were generally found within bedding planes, most commonly on top of the coalbed. The maximum lateral extent for a horizontal fracture was 265 ft at a coalbed depth of 630 ft. Horizontal fractures have been found to occur as deep as 1,145 ft. Penetration of strata overlying coalbeds was observed in nearly half of the treatments intercepted. Most of these occurrences have been interpreted to be penetrations into preexisting joints. No roof falls or adverse mining conditions were encountered that could be attributed to the stimulations." - NIOSHTIC-2

      NIOSH no. 10005572

    • Subjects:
    • Series:
      Report of investigations (United States. Bureau of Mines) ; 9083
    • Document Type:
      Report
    • Collection(s):
    • Main Document Checksum:
    • Download URL:
    • File Type:

    Supporting Files

    • No Additional Files

    More +

    You May Also Like

    Checkout today's featured content at stacks.cdc.gov