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Post by Wheldale on Sept 24, 2013 6:55:42 GMT -5
How is a shearer drum designed for producing house coal different to a drum that is used to cut coal for power station fuel? Angle of picks, less picks, no difference at all?
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Post by John on Sept 24, 2013 7:24:49 GMT -5
How is a shearer drum designed for producing house coal different to a drum that is used to cut coal for power station fuel? Angle of picks, less picks, no difference at all? It isn't, but there is still large coal produced, the screening plant isolates larger coal for crushing, some would be diverted to a smaller household coal bin.
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Post by dazbt on Sept 24, 2013 11:42:13 GMT -5
How is a shearer drum designed for producing house coal different to a drum that is used to cut coal for power station fuel? Angle of picks, less picks, no difference at all? A very good and valid questions Wheldale, there was (is) a great deal of technology and variants in drum design that directly influenced the type of product and required size, (not just for house coal/thermal coal sizing). Factors such as number of vanes, vane depths, angles, cladding, material types, pick type and size (reach, rake and clearance angles, tip type), pick angles and lacing patterns, drum revs/diameter (peripheral) speeds, haulage (cutting) speeds, torque (power available), even the type and amount of water jets, each one affecting or effecting the cutting/loading efficiency and product quality peculiar to any one particular coal face let alone different seam configurations. Drum application design and manufacture has always been an art in itself, some longwall shearer applications needed little more than a vaned drum to simply impact and load spalled coal others were successful in providing a suitable product only because of well thought out and critically designed drums. Each seam and longwall application varies (taken on end, on bord, coal hardness, toughness, friability, variations in inherent or induced loading play a part in determining "cutability", suitable variations in shearer drum design play a major part in determining how the coal is cut and resultant product size .......... given enough designed horse-power any coal seam can be extracted by pulverisation but not every customer wants 'pulvor'.
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Post by John on Sept 24, 2013 11:49:53 GMT -5
How is a shearer drum designed for producing house coal different to a drum that is used to cut coal for power station fuel? Angle of picks, less picks, no difference at all? A very good and valid questions Wheldale, there was (is) a great deal of technology and variants in drum design that directly influenced the type of product and required size, (not just for house coal/thermal coal sizing). Factors such as number of vanes, vane depths, angles, cladding, material types, pick type and size (reach, rake and clearance angles, tip type), pick angles and lacing patterns, drum revs/diameter (peripheral) speeds, haulage (cutting) speeds, torque (power available), even the type and amount of water jets, each one affecting or effecting the cutting/loading efficiency and product quality peculiar to any one particular coal face let alone different seam configurations. Drum application design and manufacture has always been an art in itself, some longwall shearer applications needed little more than a vaned drum to simply impact and load spalled coal others were successful in providing a suitable product only because of well thought out and critically designed drums. Each seam and longwall application varies (taken on end, on bord, coal hardness, toughness, friability, variations in inherent or induced loading play a part in determining "cutability", suitable variations in shearer drum design play a major part in determining how the coal is cut and resultant product size .......... given enough designed horse-power any coal seam can be extracted by pulverisation but not every customer wants 'pulvor'. I can just hear the pit Manager after you said that Daz...."Yeah burrizthe effin thing going to cut me 20 shears a day"
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Post by John on Sept 24, 2013 11:55:17 GMT -5
Back in the days when nearly every house burned coal and factory boilers burned coal, there were many pits using trepanners to provide that large size coal. We used to have concessionary coal in the Oz pits, although not many bothered with it, but, we had a small bin at side of the coal prep plant where large coal was diverted from the screens for that product. The rest went through the crushers to the main product bin to be trucked to the power station down the road, who was our only customer.
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Post by dazbt on Sept 24, 2013 12:28:28 GMT -5
Back in the days when nearly every house burned coal and factory boilers burned coal, there were many pits using trepanners to provide that large size coal. We used to have concessionary coal in the Oz pits, although not many bothered with it, but, we had a small bin at side of the coal prep plant where large coal was diverted from the screens for that product. The rest went through the crushers to the main product bin to be trucked to the power station down the road, who was our only customer. Yer've missed a bit J, trepanners weren't just used back in the days of unicorns and Robin Hood, a new breed of trepanner was demanded in the mid 1980s, there obviously was a need for larger coal in the UK right up until the end of British Coal and by coincidence perhaps, that demand was from the Nottinghamshire Area, Silverhill Colliery using the new 270HP floor mounted trepanner at least into 1988, somebody needed large coal as late as that. Even China recognised the need for 'big coal' buying the 270hp trepanner mid 1980s.
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Post by John on Sept 24, 2013 12:34:52 GMT -5
Yep, I knew there were still some trepanners around in the 80's probably well into the 2000's too as the Germans only dropped their last trepanner a few years back.
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Post by dazbt on Sept 24, 2013 12:42:11 GMT -5
A very good and valid questions Wheldale, there was (is) a great deal of technology and variants in drum design that directly influenced the type of product and required size, (not just for house coal/thermal coal sizing). Factors such as number of vanes, vane depths, angles, cladding, material types, pick type and size (reach, rake and clearance angles, tip type), pick angles and lacing patterns, drum revs/diameter (peripheral) speeds, haulage (cutting) speeds, torque (power available), even the type and amount of water jets, each one affecting or effecting the cutting/loading efficiency and product quality peculiar to any one particular coal face let alone different seam configurations. Drum application design and manufacture has always been an art in itself, some longwall shearer applications needed little more than a vaned drum to simply impact and load spalled coal others were successful in providing a suitable product only because of well thought out and critically designed drums. Each seam and longwall application varies (taken on end, on bord, coal hardness, toughness, friability, variations in inherent or induced loading play a part in determining "cutability", suitable variations in shearer drum design play a major part in determining how the coal is cut and resultant product size .......... given enough designed horse-power any coal seam can be extracted by pulverisation but not every customer wants 'pulvor'. I can just hear the pit Manager after you said that Daz...."Yeah burrizthe effin thing going to cut me 20 shears a day" Yep, every manager's aim in life, to ask daft questions, but the smarter ones had grasped that an efficiently designed shearer drum which actually cut and cleared coal efficiently was likely to give him increased tonnage as opposed to a grinding machine that only gave him power station dust.
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Post by dazbt on Sept 24, 2013 12:46:19 GMT -5
Yep, I knew there were still some trepanners around in the 80's probably well into the 2000's too as the Germans only dropped their last trepanner a few years back. So, back to Wheldale's question, where there was a recognised need for bigger coal did shearer drum design vary in order to accommodate that fact, and the answer is yes.
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Post by Wheldale on Sept 24, 2013 13:31:20 GMT -5
The reason I asked was because the lad next door works with steam loco's. He was telling me that they are using Colombian coal as they can't get big sized coal in the UK. The few faces left must be using shearer drums for the power station market.
Thanks for the replies guys!
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Post by colly0410 on Sept 24, 2013 13:51:34 GMT -5
My Dad would have loved this thread, (& this site) he was a big trepanner fan having serviced them for a number of years at Bestwood Workshops, he was always singing it's praises. When I mentioned the experimental plough face down Hucknall (B1's in Deep Soft) he said it would fail & it did.
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Post by John on Sept 24, 2013 14:01:40 GMT -5
My Dad would have loved this thread, (& this site) he was a big trepanner fan having serviced them for a number of years at Bestwood Workshops, he was always singing it's praises. When I mentioned the experimental plough face down Hucknall (B1's in Deep Soft) he said it would fail & it did. From what I remember from way back, the guys from Wollaton said a plough was tried at that pit in the 50's and was never a success. First time I saw a trepanner was at Hucknall training centre for courses to be run on it, that was the old heavy duty floor mounted machine. It was in common use during the 50's in the No6 area, Babbington, Linby, Gedling, Bestwood.
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Post by dazbt on Sept 24, 2013 14:22:17 GMT -5
My Dad would have loved this thread, (& this site) he was a big trepanner fan having serviced them for a number of years at Bestwood Workshops, he was always singing it's praises. When I mentioned the experimental plough face down Hucknall (B1's in Deep Soft) he said it would fail & it did. From what I remember from way back, the guys from Wollaton said a plough was tried at that pit in the 50's and was never a success. First time I saw a trepanner was at Hucknall training centre for courses to be run on it, that was the old heavy duty floor mounted machine. It was in common use during the 50's in the No6 area, Babbington, Linby, Gedling, Bestwood.Was it the HD trepanner used in the 1950s J rather than the 70HP?
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Post by John on Sept 24, 2013 14:31:57 GMT -5
From what I remember from way back, the guys from Wollaton said a plough was tried at that pit in the 50's and was never a success. First time I saw a trepanner was at Hucknall training centre for courses to be run on it, that was the old heavy duty floor mounted machine. It was in common use during the 50's in the No6 area, Babbington, Linby, Gedling, Bestwood. Was it the HD trepanner used in the 1950s J rather than the 70HP? Typo, sorry, 60's....
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Post by bulwellbrian on Sept 25, 2013 3:26:29 GMT -5
We did quite a bit of work at Cinderhill laboratory down various pits on the size consist of the output of both shearer and trepanner faces in the 1960's. I also remember a hand got face at Gedling and a plough in the Main Bright at Hucknall. We also did some work measuring the breakage caused to large coal by transfer points both underground and in the washeries. There was still a large demand for house coal including a considerable quantity shipped to Northern Ireland. The railways still used a lot in the early 1960's. Large coal brought in a better price than power station smalls.
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Post by John on Sept 25, 2013 12:04:29 GMT -5
Just a thought, modern longwall equipment uses "bridge stage loaders" which usually incorporates a crusher to break "spall" into manageable sized coal. Working with development driven with CM's, these also load into a ratio feeder, but like the old Crawley stage loaders, but with a crusher. It served two purposes, slowed the loading of coal onto the belt, hence the name "ratio feeder" and to break up large coal into smalls.
Either way, concession coal was still large enough as household coal...I doubt though that both mines I worked at down under could have produced enough household coal in marketable quantities....Maybe without the crushers it would have made a large difference....Just a guess, as one mine produced coal for coking, the other for power station.
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Post by bulwellbrian on Sept 25, 2013 12:42:34 GMT -5
Thinking a bit more about large coal in the old Area 6 of the East Midlands Division in the 1960's,
Babbington produced top class house coal from the Deep Soft but when production started in the Deep Hard a crusher was installed in the Deep Hard gate to put everything below 2" to preserve the price of the house coal.
Bestwood house coal was less favoured but fine for the railways - High Main seam
Calverton similar to Bestwood but all output had to go by rail due to the agreement on building the branch line.
Clifton small amount of house coal sold to local merchants, not a good quality
Cotgrave the coal prep plant was built to produce house coal from the Deep Soft but when this seam failed and production was moved to the Deep Hard the pit became power station only.
Gedling another top quality house coal pit from the High Hazles, but the Top Hard which was treated separately was more for railways.
Hucknall the Main Bright was the best house coal in the area but the High Main not so.
Linby similar to Bestwood
Radford all +1.5" coal was taken by rail to Linby and put through the washery there. no washery at Radford
Wollaton same as Clifton.
Memories get a bit faint after 40 to 50 years
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Post by John on Sept 25, 2013 15:22:19 GMT -5
Wollaton finished it's life in the Tupton seam, so no wonder it was crap coal, same with Clifton, last three working faces all at the south western end of the Tupton seam, two heading due west towards Ruddington and getting thinner and thinner...Gave me the shivers on 52's, very low.
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Post by smshogun on Feb 8, 2014 15:54:43 GMT -5
Moorgreen produced all coals, singles, doubles, trebles, power station, and large lump coal, much of the lump coal went for steam locomotives or boilers and people like Fred Dibnah and the railway preservationists were largely to blame for the resurgence and demand of lump coal.
Drum design played a part in the type of coal you could produce as did the pick design, but the major factor was the coal seam you were working.
It is a fallacy that trepanners and ranging drum shearers were different in the type of coal they produced, when a coal cutting pick hits a coal seam it only cuts where the coal is dense and in most cases the seam was created in layers, this makes the pick more akin to a rotating hammer and chisel, the first pick hits it and loosens a crack and as the second pick hits it, it knocks a large chunk of coal down.
Most coal gets reduced in size through the plough loading it onto the face chain or when travelling miles along conveyors and across multiple transfer points where it is dropped and smashes.
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