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Post by Wheldale on Dec 10, 2014 13:21:13 GMT -5
How hard was it to change direction on an advancing face ie swing the face to the left. Also what was the process of changing direction?
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Post by John on Dec 10, 2014 13:41:26 GMT -5
How hard was it to change direction on an advancing face ie swing the face to the left. Also what was the process of changing direction?
Same if the seam starts to rise, control the face conveyor by putting sticks on the face side to get the conveyor at an angle, once the cut is established you start to rise with the seam. If the seam starts to dip, lift the rear of the pans and put sticks under it.
When I was an apprentice, the head surveyor screwed up big time, cost him his job and probably his mine survey ticket, the face was off line by 12 degrees, doesn't sound much, but we were on the edge of the safety zone between us and water bearing strata.
The face was swung over 12 degrees to the left.
Looked odd after a couple of weeks seeing the next shift coming up the maingate through the start of the turn. |
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Post by erichall on Feb 20, 2015 10:01:33 GMT -5
We swung 3 faces at High Moor. I was involve in the last when the face was swung through 17.5 degrees. It inolved 'pushing the main gate as fast as possible ' and holding back the Tail Gate.Periodically, a full shear would be taken, This was then followed by a series of shears staring at varying points up the face. It had to be done in a specific order, but the process was relatively simple.The main problem lay in the main gate, where the switchgear was mounted on overhead rails and would easily advance with the face, until such a point was reached when the transformer had to be advanced and an extra length of Double wire armoured cable had to be inserted. This was timed where possible for a weekend.All in all it proved a relatively simple process provided that the pre-arranged schedule of 'fly cuts'was adhered to. The whole idea was to get the fault we were carrying off the face line and realigning the angle of the coal. The original line was proving very difficult to cut and the fault negotiated, until the face was reailgned, when the face advance 'took off like an express train
One of the Oficials produced a paper entitled 'From Failure to Success in 17 and a half degrees'
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Post by Wheldale on Feb 20, 2015 13:27:28 GMT -5
What happens with the conveyor belt? It has to go in a straight line, so is there a series of conveyor belts with short runs? Or is the gate constructed to "straighter" during a turn?
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Post by John on Feb 20, 2015 13:54:58 GMT -5
What happens with the conveyor belt? It has to go in a straight line, so is there a series of conveyor belts with short runs? Or is the gate constructed to "straighter" during a turn?
For sharp bends, there are special tracking rollers now available, check the photos of one at Boulby Mine on their Cleveland Potash site, there's a "bendy" conveyor made by Joy on that site.
I dug Cliftons abandonment plans out after seeing Erics post, the face swing over 10 degrees is not shown on the plans, oddly too, it shows a block of coal between 10's and 12's where the face was swung to the left 10 degrees. The two faces shared the same tailgate, 10's finished after convergence closed it up one shift, crushing all the Dowty chocks and shearer.
12's was out of line through a serious survey error that cost the head surveyor his job. He'd screwed up big time and we were very lucky the mistake was picked up or the pit would have flooded with devastating results. We were within a safety barrier between us and the Bunter water bearing strata. I'd hazard a guess the surveyor lost his mining accreditation to his survey ticket over that episode.
The "rain" in the M/G and throughout the face must have had a few mining engineers panicking, especially after we were discovered to be well into the safety barrier. |
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Post by erichall on Mar 5, 2015 7:57:42 GMT -5
Surprising how a belt will run 'out of line' , but if my memory serves me correctly, we held onto the Maingate belt until the turn was completed, then put in a new conveyor, back at the start of the turn. Funnily enough, if I'm correct, I believe our troubles started only when we put the short belt in, but these were quickly overcome as the belt length improved.
Another way of course, is to keep extending the stage-loader, until a suitable length is reached. Not as time-consuming as one might think, and can be achieved by ensuring the Main Gate is sufficiently advanced, so this can be done during down-time i.e. between Afts & nights, and done better by a designated team, set up for the purpose.
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Post by John on Mar 5, 2015 8:59:40 GMT -5
Surprising how a belt will run 'out of line' , but if my memory serves me correctly, we held onto the Maingate belt until the turn was completed, then put in a new conveyor, back at the start of the turn. Funnily enough, if I'm correct, I believe our troubles started only when we put the short belt in, but these were quickly overcome as the belt length improved. Another way of course, is to keep extending the stage-loader, until a suitable length is reached. Not as time-consuming as one might think, and can be achieved by ensuring the Main Gate is sufficiently advanced, so this can be done during down-time i.e. between Afts & nights, and done better by a designated team, set up for the purpose.
Another question, on advancing faces, how did they build the road side packs with an advanced gate road?? |
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Post by erichall on Mar 10, 2015 6:57:08 GMT -5
[
Eric, when approximately, did the NCB start advancing gate headings to eliminate the dangerous ripping lips and stable holes?? It seems such a brilliant idea and should have been incorporated in power loader faces from day one. Not only from the safety aspect, but reducing face teams by 8 members, plus eliminating shotfiring operations.
Another question, on advancing faces, how did they build the road side packs with an advanced gate road??
[/quote]
Like the introduction of mechanisation, John, this happened over a period of time, it was introduced in different areas at different times, and in different pits at different times. I would imagine that the whole period came over a period of something like 15 years, in my personal experience.
It also happened in many different ways.Take my own experience as an example. I started in 1958, and at Barrow Colliery in S.Barnsley Area. we had some hand filling in the Lidget Seam, the lower seam , the Fenton Seam was gassy and used full gob stowing,whilst the Swallow Wood Seam, a later area to be mined, was one of the first to become mechanised. Here the layout was a conventional face with stableholes, except that loading was done down the rib side and via short slit gates, leaving the MainGate Rip 'free'. On the introduction of power loaders, the machines were the early Floor-Mounted Trepanners, complete with two undercutting jibs, each of which had to be swung out of operation at the end of a shear, and locked into position under the now-trailing Trepan Head
S Barnsley was in the forefront of trying Stablehole Machines, which cut the full stable hole, and of the trial of various Ripping machines.
In 1968 I moved into N.Derbyshire area, and their experience eventually 'ended' by the formation of advance heads driven by Dosco Mk.1 Roadheaders, these to be eventually replaced by the Mk.2 and in special cases where the roof turned to the Permian sandstone by the Mk.2a
In general, the heads were supported on 4 piece arches, the face side leg being cut at the height of the seam This was fixed by a yielding fishplate, the other two joints being conventional fishplates. Across the face entry were run 2 extra long girders with a triangular clamp running across the width of the girders and attached to the top half of the cut leg of the arch, the whole supported by Dowty Hydraulic props, front and rear. The nearer props were removed prior to the approach of the machine, usually a DECMT, and transferred to the rear of the convetor. After shove over, the cut sections were replace and affixed to the arch with conventional fishplates. The packside would be built using wooden chocks infilled with brown paper bags filled with waste. The side of the gate would then be completed by the fitting of corrugated, interlocking sheets.
Seems now to be a complicated system, but it worked, and ventilation was always maintained.
The manpower would be 2x4men teams in the advance head (often reduced to 3) and a face team of 13. The faces were 200 metres long, supported by Dowty 5 legged chocks, and a usual shift would reveal 2 cuts. It was often the practice in reasonable conditions for the team to split into 2, with half taking the machine one way whilst the other took over to take it the other way. The gateside team of 3 men each would stay at their own gate.
There were several versions of this system at various pits, but in general this was the scheme that worked.
If I knew how to sketch, I could add a few sketches, but I don't, unfortunately.
Eric.
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Post by John on Mar 10, 2015 11:49:38 GMT -5
I'm surprised it wasn't used everywhere Eric, especially under Robens who was always trying to cut costs. One the safety aspect, it got rid of that dangerous ripping lip, reduced the use of explosives, and as previously mentioned, reduced face manpower.
I have some photos on my external hard drive sent to me showing the gate end roadway supports in an advanced heading face.
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joss
Trainee
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Post by joss on Aug 31, 2018 23:24:04 GMT -5
Surprising how a belt will run 'out of line' , but if my memory serves me correctly, we held onto the Maingate belt until the turn was completed, then put in a new conveyor, back at the start of the turn. Funnily enough, if I'm correct, I believe our troubles started only when we put the short belt in, but these were quickly overcome as the belt length improved. Another way of course, is to keep extending the stage-loader, until a suitable length is reached. Not as time-consuming as one might think, and can be achieved by ensuring the Main Gate is sufficiently advanced, so this can be done during down-time i.e. between Afts & nights, and done better by a designated team, set up for the purpose.
Another question, on advancing faces, how did they build the road side packs with an advanced gate road?? |
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Post by ericfromclowne on Nov 22, 2018 15:32:47 GMT -5
Hi, Joss.
Have moved to Buxton, funnily enough, close to the Health & Safety Exec. Site (used to be part of Safety in Mines , I believe) where they used to test all the new oil lamps, powder, stone dust barriers etc in underground galleries, and haven't used the site recently.
As for the Advance Headings, these are as with many things a matter of taste & local use. They are ,IMO better than ripping lips , but are not without their own problems, not the least being at the point where the face entrance is. Her, when the machine goes in & out, there remains a 'black spot' where the arches are not complete,m in order to allow the machine in and out. It was in fact at this point I encountered my first fatality, when a chap was timbering the roof immediately on the corner, always a weak spot.
As for timing, it was in the early '60's that the N Derbys. Area was predominantly using advance headings. various pits had versions of their own systems for 'packing', the far side of the gate was left solid, whilst the goaf side pack consisted of chock nogs sometimes infilled with paper bags full of dirt. Tinning in of the arches was imperative to maintain ventilation.
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