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Post by Wheldale on Dec 16, 2012 6:52:16 GMT -5
In this photo of a heading at Wheldale. They look to be roof bolting. In the bottom left you can see a cutting head, is that from a Dint Header??  |
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Post by John on Dec 16, 2012 11:30:36 GMT -5
In this photo of a heading at Wheldale. They look to be roof bolting. In the bottom left you can see a cutting head, is that from a Dint Header??
We used Heliminers for development in Oz....
Why the bolting in a steel supported road? ? Doesn't make much sense.. |
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Post by shropshirebloke on Dec 16, 2012 14:55:18 GMT -5
Back in the late 70s the only place I can remember roofbolting being used was as additional support in steel supported roads - roof bolts with two-part epoxy resin packs holding up weldmesh before the rings and tins went in, when the roof was a bit dodgy.
I couldn't believe it when I heard that the Yanks used it as their main means of roof support - then that it was being used in the same way here. Surely Bilsthorpe in 1993 should have been a wakeup call?
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Post by Wheldale on Dec 16, 2012 15:02:09 GMT -5
The problem with the bolts at Bilsthorpe was the system of skin to skin mining. Each panel was next to the next panel, no pillar inbetween the two gates. The bolts did thier job they were designed to do, i.e. tie the different layers of strata together to form a solid "beam" of rock. The problem arose as there was no pillar support on one side of the roadway (this was the old roadway of the privious panel). This created a cantilever effect of support which failed resulting in the tragic accident.
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Post by Wheldale on Dec 16, 2012 15:07:07 GMT -5
In this photo of a heading at Wheldale. They look to be roof bolting. In the bottom left you can see a cutting head, is that from a Dint Header?? Can't help you there, during my NCB years, I only worked in drill fire and load out with M&C3 loaders and later with Dosco Mk2 Roadheaders.
We used Heliminers for development in Oz....
Why the bolting in a steel supported road?? Doesn't make much sense..I'm not sure if they are bolting, I think they are drilling to insert a dowel. I'm not sure what the difference is? I think a dowel helps to control bad ground but not support it? Just to the left of the drill looks like a large break running parralel to the drill. This doesnt look like a fault as the seam lines up either side. |
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rac
Shotfirer.
Posts: 87
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Post by rac on Dec 16, 2012 15:15:28 GMT -5
In this photo of a heading at Wheldale. They look to be roof bolting. In the bottom left you can see a cutting head, is that from a Dint Header??
We used Heliminers for development in Oz....
Why the bolting in a steel supported road?? Doesn't make much sense..certainly looks like a dint header worked with them in the 70's/80's and looking at the heading face you can see where the picks have gone up and down,also was always on square work taking about 7ft in height very often used to "head out" for retreat faces.at one of the pits i worked at "oxcroft" in the derbys area if i remember correctly they had a record in the 70's for something like 100mts advance in a week. not got a clue what the drilling is about though! test bore maybe? |
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Post by John on Dec 16, 2012 15:29:40 GMT -5
Back in the late 70s the only place I can remember roofbolting being used was as additional support in steel supported roads - roof bolts with two-part epoxy resin packs holding up weldmesh before the rings and tins went in, when the roof was a bit dodgy. I couldn't believe it when I heard that the Yanks used it as their main means of roof support - then that it was being used in the same way here. Surely Bilsthorpe in 1993 should have been a wakeup call?
BC was just asking for an accident not having a barrier pillar between both faces, I was really surprised the Inspectorate allowed it!!
We did have roof failure on one main gate right at the face line, just some weak strata, or maybe it wasn't bolted early enough, bed separation, no one will ever know. Cost us a couple of weeks of lost production... |
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Post by cortonwood on Dec 16, 2012 15:32:48 GMT -5
we used to secondary bolt a lot of the time john in 1 or 2 of the pits i worked in,both in square work and arched work,and it did pay dividends. it was wierd when the face was retreating back and the main gate was collapsing,you could see 8 foot bolts more than doubled in length with all the weight they had been carrying. in the picture the end of the cutting head looks like a dintheader,used in all the gateroads at Barnburgh Main where I worked. In this photo of a heading at Wheldale. They look to be roof bolting. In the bottom left you can see a cutting head, is that from a Dint Header??
We used Heliminers for development in Oz....
Why the bolting in a steel supported road?? Doesn't make much sense.. |
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Mick
Shotfirer.
Posts: 163
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Post by Mick on Jun 22, 2013 14:32:56 GMT -5
Not sure this picture is of Wheldale first the seam is to thick and i can never remember them roof bolting on a face line or heading,we did alot of doweling when we tuck the first cut on a new face just to give it a start but we put wood dowels in then.
Mick.
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Post by John on Jun 22, 2013 15:59:30 GMT -5
Reading back I missed something, we used to take bolting for granted...First and foremost, bolting isn't for "roof support" per say... The Pillars are the main support in any mine, be it barriers between faces or either side of a road being driven.
What the roof bolts are doing is "binding the strata together" to form a "rock bridge" between either side of the road.
Pillars in any form are what is supporting the strata.
In the two Australian coal mines I worked in, the above applied together with "W" straps, they were to stop the roof breaking up, a bit like lagging between rings.
If you had gone underground in one of British Gypsum's gypsum mines, the only support you would have seen during my time there were the 7 yard square pillars, nothing else supported the roof. Shane told me, since using continuous miners they are roof bolting.
I was used to seeing 10 foot bolts used in all roads both in Oz and when I worked at Boulby Potash mine. Something else thats done in some mines, the ribs are bolted and meshed where they present any danger due to weight breaking the pillar ribs out.
I lost a good mate at Boulby where a huge piece of rib rolled over and crushed him and a miner.
Now do you recall the Crandall Canyon mine disaster in Utah a few years back? That roof was heavily bolted throughout the mine, it wasn't that that got those miners, it was caused by breaches of long learned lessons and sheer stupidity on the mine owners part. They had been extracting the pillars and had not left enough roof support.
The previous mine owners had left several large barriers between longwall panels to support the roof, they also left a huge coal barrier between two sections of that mine... Those were the barriers the present owner was recovering, but emphatically denied he was allowing it to the media... This caused massive convergence throughout that mine ending in several men losing their lives.
I'm not sure now where leaving barriers was first considered good mining practice, but think it was Northumberland during the 18th century.
Anyway, bolting is a proven technology, BUT, it was always stressed on mining crews to bolt as early as possible after mining an area to prevent "bed separation" Once that occurs, bolting is for all intents and purposes, useless, and poor roof conditions will prevail.
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Post by Wheldale on Jun 22, 2013 17:25:21 GMT -5
Not sure this picture is of Wheldale first the seam is to thick and i can never remember them roof bolting on a face line or heading,we did alot of doweling when we tuck the first cut on a new face just to give it a start but we put wood dowels in then. Mick. My dad got me the photo from the Wheldale offices, might not be from Wheldale at all. The original is a bit clearer, the seam is in the middle of the cut, I'm thinking the shiney rock is coal , dull rock is mudstone/ dirt. When looking at the two men in the picture I'm guessing the coal seam is about 4 foot thick. Was that thicker than the flockton seam at Wheldale? |
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rac
Shotfirer.
Posts: 87
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Post by rac on Jun 27, 2013 14:47:54 GMT -5
i would say definately a dintheader looking at the square girder work and the pick marks going up and down on the coal,they used to take about 6ft 6ins of height out if i remember right--not very good if you were a tall person.as regards the bolting/dowelling hmmmmm ??
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Post by fortythreesflyer on Aug 6, 2018 10:04:38 GMT -5
Not sure this picture is of Wheldale first the seam is to thick and i can never remember them roof bolting on a face line or heading,we did alot of doweling when we tuck the first cut on a new face just to give it a start but we put wood dowels in then. Mick. My dad got me the photo from the Wheldale offices, might not be from Wheldale at all. The original is a bit clearer, the seam is in the middle of the cut, I'm thinking the shiney rock is coal , dull rock is mudstone/ dirt. When looking at the two men in the picture I'm guessing the coal seam is about 4 foot thick. Was that thicker than the flockton seam at Wheldale? Yes flockton was only about 2ft10 to 3ft at best. Haigh moor was about 5ft max. |
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? Doesn't make much sense..
