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Job Breakdown Sheets
Breakdown No. 14
Withdrawing Props and a Bar or Strap
1: Examine the working place.
2: Set anchor prop.
3: Attach Sylvester.
4: Remove first prop.
5: Remove bar.
6: Remove second prop.
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Choose a position from which the work can be performed safely.
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| (b) |
The top of the anchor prop should be inclined in the direction of pull, i.e., towards the prop to be withdrawn.
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Pass the short chain which is attached to sword of the Sylvester around the foot of the anchor prop so that the hook passes under the chain.
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Pass the hook of the long chain around the top of the first prop to be withdrawn, in this case the one nearest the goaf. Loop the chain through the hook, pull the chain tight and place a link in the eye of the Sylvester box. A prop extractor may be attached to the top of the prop to assist movement.
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Attach the spare chain to the top of the second (the nearer) prop.
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Operate Sylvester lever, withdraw the first (rear) prop.
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Take chain from round the prop.
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Attach the freed chain to the bar. Hook it to the link or eye, whichever is provided. If neither is provided wrap the chain round the bar.
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Couple chain to Sylvester box.
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| (c) |
Operate Sylvester lever and remove the bar.
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Pull on chain attached to prop and draw out the prop.
If whilst removing the bar the roof has collapsed and buried the prop, attach the chain to the Sylvester.
Operate the Sylvester lever and draw out the prop.
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