Longwall Records.

[John]

Try this!!!

In the past year, Xstrata's Oaky Creek North mine set several new Australian longwall records using Eickhoff SL 750 with EiControl automation. These included a one month longwall tonnage of about 1.5 million tonnes.

[erichall]

Sounds like a 'Manager's Dream Come True'

The only problem with records is that they only tell part of the story. Many salient facts are omitted, such as a) Type of coal cut b) thickness of seam c) percentage of seam extracted etc. etc.
Whilst not belittling the record, since all records have to be earned, having worked in what were at the time record-breaking feats, I often found that performance had often little to do with true skill, but more with excellent conditions.
I spent most of my working life working in 3-4 foot seams, often in trying conditions, and had some of the easiest times when we were breaking records.
Still, it's nice to know what can be achieved given the correct equipment, conditions and will.

[John]

In all the time I worked at Angus Place in NSW, most of which was spent as longwall electrician or leading hand electrician, I only ever saw bad conditions twice on the longwalls I worked on, that was just over seven years.

One was approx mid face when we had a major roof fall that traveled into the face itself, we lost several weeks of production over that one. And the other was when we had a large roof fall in the M/G just ahead of the face, lost about two weeks due to a wrecked stage loader, plus roof repairs.

Now UK, different matter, three faces to convergence, white wall in 51's, heavy roof in a M/G, requiring a back rip, M/G end of 43's fell in, face advancing too fast for the rippers to catch up. Instead of stopping the face for a shift, they just kept cutting, had over nine yards of ripping!!!! Scary too, I'd just gone under that lip about an hour earlier to get on the face.

[John]

Incidentally, the Manager at Angus Place was Mick Potter, ex pat Brit like myself, then was replaced, he then became Longwall Manager in charge of production and planning for all future longwalls. Nice bloke, knew his job, I never asked him, but presume he'd been a Manager in the UK. Same qualifications requirement as UK's.

[dazbt]

Any type of productivity record can only be claimed against comparative parameters, but that can be as detailed or nonspecific in identification as required, i.e. the old Coal News back page ‘league tables’ compared seam sections, nothing else, not seam hardness, cuttability, transportation efficiencies, seam geology, colliery capabilities and capacity, real costs, (the OMS figures often being at best unreal, at worst a joke), or consideration bein given to a million other variable factors and nor should it have, records are and always have been relative to a an easy to grasp comparison of relative affects and effects. Nobody could ever argue about a colliery claiming a total tonnage output such as the Oaky Creek world record, the facts are that the colliery tonnage is (was) the world’s highest, it is the most that any colliery has produced (or was at that time), it doesn’t matter how or dictate from what quality, produced by whom, in whatever condition, from any particular seam section or condition, it is simply a claim on tonnage produced and should be accepted as such. What I will say is that the ‘record production attempts and claims’ that I have been involved in the UK and abroad (and that is more than a few), I can say that each and every one has been ‘fudged’ by individual or common management acclaim seeking.

[John]

With high HP machines these days, does seam hardness come into the factor??

I have seen a 120HP heliminers bounced out of a heading with the head mounting bearings wrecked, but that was cutting through a sill, not coal. Also bearing in mind, that heliminer was designed to cut coal and was about 20 tons lighter than it's heavy duty hard rock version.

But shearers today have reached the magic 1000hp mark now, would there be any coal seam too hard for a machine of that capacity???


BTW Daz, did you find those AM500 pages I posted yesterday???

[dazbt]

Jul 8, 2011 13:48:29 GMT -5 John said:

With high HP machines these days, does seam hardness come into the factor??

I have seen a 120HP heliminers bounced out of a heading with the head mounting bearings wrecked, but that was cutting through a sill, not coal. Also bearing in mind, that heliminer was designed to cut coal and was about 20 tons lighter than it's heavy duty hard rock version.

But shearers today have reached the magic 1000hp mark now, would there be any coal seam too hard for a machine of that capacity???


BTW Daz, did you find those AM500 pages I posted yesterday???

Yes hardness does still affect performance and will always play a relative part in determining the overall efficiency of any cutting machine. Horse Power is to some extent irrelevant when compared to effect5 of the many other factors, both of machinery efficiency (design and operation) as well as the friabiliby and cuttability of the mineral being exploited. A badly designed 500HP machine applied to a specific seam or face application could well produce much less effect on cutting/production capability than a well designed application of a 200HP shearer. In a nutshell even a 1,000,000 HP machine couldn't cut even the softest,/easiest coal seam with a cutting element that wasn't effieciently or appropriately designed to suit those specific conditions. Lessons well learnt by Anderson and other coal cutter manufacturers who stepped 'neatly' into foreign situations of unexpected or under appreciated hard coal applications or known conditions. Design factors of shearer drum, pick lacing patterns, pick type/design, drum scroll angles, drum speed and rotational direction as well as machine clearance, all had to be rethought and applied differently to machine capabilities and expectancies, increased HP applications alone just doesn't do it.

Yes, thanks J, I did appreciate the AM500 schematics and diagrams, just as I remembered them .......... the AM400 diagrams would have been even better though. The AM500 diagrams were were part of the standard Anderson Strathclyde parts list issued with each particular machne and configuration.

[John]

One of the first faces I ever went on, 41's in the Deep Hard seam, around 1965, had a 16/125 shearer and a leading bedframe with an AB15 cutter as a precutter mounted on it. Which was later discarded.
That was taking around 42" of coal. I never quite understood that set up, as at the far south west of the pit, same seam, thicker though and cutting around 60". Same sized shearer, 16/125 just with a larger drum.
One thing that was done at Clifton though that I have never seen elsewhere, the pick boxes on new drums were burned off and rewelded back on at different angles, I presumed to suit our conditions.

[John]

Back on topic, I see a couple of Australian collieries are going for 7million tonnes per year now! That's from one face too, plus development coal.
I see Angus Place is almost to 3.5million tonnes per year.

[dazbt]

Jul 8, 2011 15:27:34 GMT -5 John said:

Back on topic, I see a couple of Australian collieries are going for 7million tonnes per year now! That's from one face too, plus development coal.
I see Angus Place is almost to 3.5million tonnes per year.

7million tonnes per year from one Longwall (even plus development coal) is absolutely mind boggling innit?

[John]

Jul 9, 2011 8:12:26 GMT -5 dazbt said:

Jul 8, 2011 15:27:34 GMT -5 John said:

Back on topic, I see a couple of Australian collieries are going for 7million tonnes per year now! That's from one face too, plus development coal.
I see Angus Place is almost to 3.5million tonnes per year.

7million tonnes per year from one Longwall (even plus development coal) is absolutely mind boggling innit?

It is when you look back at output when we first started in the industry!
A slow crawl along a low face compared to a steady walk at side of a shearer who's cutting speed we'd never have dreamed of in seam heights we wished for!!

Angus Place while I was there was cutting more than 9000 tonnes a day, if the belts could have taken the coal, we'd have been cutting 1000 tonnes an hour! The shearer was only hauling at half speed most of the time... Now they have a large capacity belt system and surface handling scheme.

The high capacity faces are in Queensland.

[John]

www.uow.edu.au/eng/longwall/html/qld_north.html

www.uow.edu.au/eng/longwall/html/qld_cent.html

NSW Longwalls.

www.uow.edu.au/eng/longwall/html/nsw_sout.html

www.uow.edu.au/eng/longwall/html/nsw_west.html

www.uow.edu.au/eng/longwall/html/nsw_newc.html

www.uow.edu.au/eng/longwall/html/nsw_hunt.html

Impressive figures, also look at the size of shearers used these days!! The Japanese only have one Mitsui machine, they tried so hard to get a "foot in the door" too in the 80's.

[John]

Although, 20 mile Coal Mine in Colorado has some impressive output figures too.

The Twentymile longwall coal mine is located 30km south west of Steamboat Springs in north-western Colorado, USA. It is the world's most productive underground coal mine in terms of output per man-year. The mine was developed by Cyprus Amax, which sold it to the German company, RAG Coal International, in 1999. In 2004, RAG in turn sold Twentymile to Peabody Energy as part of its divestment programme for its US and Australian assets.

The mine's annual production depends on its customers' requirements. In 2005, it achieved another record in terms of output with 8.7Mt of power station fuel, significantly higher than the 7.0–7.3Mt/y. achieved in previous years. The mine has a labour force of some 240, plus 80 salaried staff. Peabody installed a new longwall system at the mine during 2006, with the aim of increasing its output to 10.9Mt/y by 2008.

The mine opened in 1983 with initial production from a small room-and-pillar operation. Longwall development began in 1987 with the first face commissioned in 1989. Since that time, Twentymile has produced a cumulative total nearing 100Mt of coal, with Peabody planning major investment in new longwall equipment for the mine during 2005. Twentymile received a state environmental award for the success of its discharge water-treatment programme in 2005.

[John]

A bit more on 20mile mine, note the shearer cutting speed!!!


Equipment, Process, and Output

Mining equipment responsible for stripping the faces of the mine’s blocks includes a Long Airdox Electra 3000 double-drum shearer with a capacity of 174 face supports. Other equipment involved are an armored face conveyor and a stage loader made by Deutsche Bergbau Technik. Once the coal is stripped away, it is loaded onto a conveyor system capable of handling 5,000 metric tons of coal per hour.

Shearing equipment is used to cut along the face of the panel, in this case, at 40 meters per minute, cutting 35.4 inches (90 cm) of coal each time it the shear passes the face. Each shift typically completes as much as two production cycles, accounting for a daily output as high as 46,340 tons mined. The shearing equipment is monitored by a computerized system that shuts down when the face output has reached its maximum rating. The shut down prevents the conveyor system from experiencing potential malfunctions brought on by overloading the system.

The geology of the mine calls for rock to be extracted along with the coal. Although not conventionally done, this prevents the rock-coal mixture from infusing with the coal. A specially designed conveyor system and chute was constructed to facilitate this process.[1]

When the materials are conveyed out of the mine, some are shipped directly to customers and others undergo a washing and screening process. Approximately 95 percent of the output is crushed to -1.96 inches (-50 mm) by primary crusher equipment. Once crushed, it is loaded onto unit trains and transported to customers.

The mine broke records with an output of 8.7 metric tons of power station fuel in 2005, a production considerably higher than that of previous years, which amounted to 7.3 metric tons of coal.

Since the beginning of the mine’s production, it has produced more than 100 metric tons of coal.[2]

[dazbt]

I did a rough calculation earlier based on an estimated face length of 250 metres, 2.25m section and 0.75m web, to achieve the 7m tonnes (all from the Longwall) the sheare would have to be working 24 hours a day for 6 days per week throughout the year at speeds continuously of 32fpm and as at Newlands Northern then that speed would be doubled (uni-di) approximately 19.5mpm absolutely non stop, with no downtime whatsoever in those 6 days per week, the US machine speeds are probably nearer the mark accepting nominal levels of machine downtime and other stoppages ................ Sheesh !!!

[John]

From what I gather, most top producing collieries now work seven days a week Daz. Note the manpower at some of those collieries, in excess of 400 miners/tradesmen then officials. That's a clue to continuous shifts.
I base that on Angus Place when I worked there, three seven hour shifts production, night shift, seven hours maintenance, five days a week. Total manpower was around 350. But we had a lot more surface workers than US mines, plus elecs didn't do fitting work and other mechanical duties US tradesmen do. Both UK and Australian mining laws make it difficult to practice two trades.

Oddly enough, down time from breakdowns was minimal, equipment these days seems to be more reliable, and/or better maintained. Some of the niggly things that used to cause stoppages way back seem to have been overcome.
Other things that do go wrong seemed to have been more reliable years back. Remote diodes for pilot circuits seemed to nag me more often than they did in the 60's through to the 70's. Probably more "spikes"?? who knows.

I think most of the problems during my youth were the old contract PLA, machinery was pushed beyond the limits of it's design, like the shearer cutting in flit speed, overloaded conveyors etc...

A lot of which stopped as the NPLA took a hold, miners had no reason to push the machines beyond design limits then.

I worked a different shift system at Boulby Mine. There it was 24 hours production seven days a week with essential maintenance carried out on Saturday day shift. Fair enough it was bord and pillar work.
Mineral winding was usually two shifts a day, seven days a week, sometimes starting around noon on days, depending on what bunker space was left.

[dazbt]

I'm pretty sure that these 'super pits' will be working 7 days, I stuck the nominal 1 day per week in to offset, maintenace and possible planned stoppages for whatever other reasons. I believe that many shearers and AFCs etc were sold on contractual payment completion based on high figures of machine availability, British Coal expected 95% and probably settled for something nearer 55%, I can't see the modern day Coal Barons of the USA and Ozz being quite so flexible in acceptance of machine unreliability.

[John]

You should see a face move Daz, it's planned out perfectly, all staff get a copy of the check sheets, everything is planned to the last nut and bolt to save time.

Last few shears the face is meshed and bolted, then last shear final mesh and bolts are installed, rails are already into the last cut through, in the M/G which is a turn really.
Stage loader is split and pulled out the way, while the two drums are removed from the shearer and loaded onto a flat top and sent to surface. We had a special flat top for the shearer with a home built ramp and racks welded to it, the shearer was driven onto the flat top, cable and hoses dropped off, machine chained down and sent to surface to be checked over and work carried out in the surface shops.

AFC dismantled, sent to surface usually to be checked for cracks and repaired as necessary.

Then shields removed using an LHD, starting with the T/G unit, loaded onto a flat top and taken to the new face one by one using a diesel loco. Another team installs them as they arrive and pressurizes them with a spare pump. As they are removed, the face is timbered and wooden chocks are built to stabilize the face.

Once all shields are installed on the new face, the chain is run out and fed through the pan line as it's installed, pan sides are bolted on and the chock relay bars coupled up.

When all but the last few pans are installed, the stage loader is brought in and installed. Shearer brought to the M/G and driven on to the AFC, M/G AFC drive installed built up and chain linked together. Stage loader coupled to AFC drive, all cables run out, signal cables coupled throughout the face.

All this is going on simultaneously so that there are as few delays as possible.
Final electrical installation, belt coupled and tested. Face cleaned up and ready to start production.
A full face move used to take around eight weeks, was better planned and eventually took around three weeks.

The face was fed at 11Kv to two large nitrogen cooled transformers, I forget the KVA ratings now, probably 750Kva each. They supplied the face at 1.1Kv, two banks of FLP GEB's made in Australia by CMA...(Cable Makers of Australia) They were very similar electrically to Baldwin and Francis GEB's. Face signalling and communications was DAC..(Derby Automated Consultants). I don't recall the make of AFC or the drives. Chocks were Dowty with "Dowvalve" electronic controls.
The cost was probably around $80 to $100 million, which by now has doubled in cost. So you can see why the coal owners want reliability!! Although with the price per ton of coal today, it wouldn't take long for a return on their investment. Around 8 months to one year, depending on operating costs.

[John]

I forgot to add, the gate belt had an automatic loop take up, some times on swing shift we had to remove a section of belt structure if each shift had done well. Didn't take very long, but of course, while this was going on production suffered.
Night shift removed all the excess belt from the loop take up after they'd done a belt retraction, that was done every night.