Sylvester's prop withdrawer is a machine used to safely withdraw support props and cogs in underground mines. It consists of long and short pins, chains, and a ratchet mechanism. It allows props to be withdrawn from a safe distance without workers going under unsupported roof areas. The withdrawer is attached to an anchored prop and uses its lever and chain system to twist and loosen support props or trigger the release of cogs. It allows multiple props to be removed in a single operation efficiently while maintaining worker safety. Precautions like using temporary props and taking shelter must be followed when using the withdrawer.

1. SYLVESTERS PROP
WITHDRAWER
BY:-ADITYA KU. VERMA
G.E.C JAGDALPUR
MINING 8th SEM.

2. INDEX
 What is Sylvesters prop withdrawer ?
 Constructional features and diagram ?
 Place where it is going to be used ?
 What is the working principle ?
 How to withdraw prop and cog ?
 What is the reason behind using this ?
 What kind of safety measures should be taken ?

3. SYLVESTERS WITHDRAWER

4. WHAT IS THIS ?
 Withdrawer is specially suitable for use to
withdraw the prop and cog in underground
mines.
 Diagram :-

5. DIAGRAM :-

6. CONSTRUCTIONAL FEATURES
AND DIAGRAM
 Long pin
 Short pin
 Short chain
 Long chain
 Conway
 Sword comb / Ratchet

7. SPECIFICATIONS
 Weight of Sylvester m/c , 15 kg
 Weight of 4.5 mm x 10 mm , 10 kg

8. WITHDRAW IN CASE OF PROP
SUPPORT !

9. PLACE WHERE IT IS GOING TO BE
USED ?
 In goaf area
 At Completely extracted sites
 At reopening of sealed off
area

10. WORKING PRINCIPLE !
 Sliding with the help of Rack_pinion and then
lock !

11. BEFORE WITHDRAWL OPERATION
 Check the availability of spare Chain.
 Attach spare chain to the next prop to be
withdrawn, so that it is not necessary to go
under root which may be unsettled.
 Start withdrawing with most remote prop and
then the others in turn working towards safe
roof at all times.

12. STEP I
Set an anchor prop inclined towards the prop to be
withdrawn, and with the head inserted into a notch
made in the roof.

13. STEP II
Pass the short chain which is attached to the sword
of the Sylvester round the foot of the anchor prop
so that the hook passes under the chain.

14. STEP III
Pass the hook end of the long chain round the top
of the prop that is to be withdrawn. Loop the chain
through the hook, pull the chain tight, and place a
link in the eye of the Sylvester box

15. STEP IV
Operate the Sylvester until the prop is released.

16. STEP V
Pull the released prop from beneath the unsupported
roof either by means of the Sylvester chain, or by
means of a long bandied pick.

17. NOTE :-
 Hold fast assembly is to be used to enable the
full length of the ratchet bar to be re-used
without releasing the load in case the prop has
not been made sufficiently loose in first travel.
 To withdraw props offering adequate
resistance to the root i.e. approaching 15
tones, by a direct pull is beyond the capacity of
devices based on Sylvester principle. A
twisting hooks of 30 mm

18. DIAGRAM :-

19. Withdraw in case of cog support !
1
2
3
4
1 2
 1)Firstly drawn
 2) Secondly drawn
TOP SECTIONAL VIEW

20. STEPS TO RELEASE COG !
 Test the roof round the chock and set a temporary
prop.
 Stand in a safe place and, using the long handled
hammer, strike the rear release trips
 In the same way release the trips on the face side.
 This will release the chock, the pieces of which
should then be gathered together and stored ready
for future use. Use the long handled pick or pout to
recover the chock pieces from the unsupported
area.

21. RELEASED COG !

22. WHAT IS THE REASON BEHIND
USING THIS ?
 Mainly safety point of view.
 Can be withdrawn 2-3 prop in single operation.
 Can be operated from a safe place
 Easy to handle.
 More efficient work.

23. WHAT KIND OF SAFETY
MEASURES SHOULD BE TAKEN ?
 By taking a safe shelter
 By adopting all safety wearable things

24. THANKYOU