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Z faces
Dec 18, 2013 6:18:20 GMT -5
Post by gadge on Dec 18, 2013 6:18:20 GMT -5
I might add for those that don't know, Polar Ajax is a powerful explosive, only it's not allowed to be used in coal or ripping lips. Polar ajax was made by ici Driftex was made by ecp , both were P1 types of explosives only allowed to be used in solid stone ,cross mesures drifts and shaft sinking and only where no coal was present and firedamp readings we,re below a certain level . it was strong stuff and could give you a throbbing headache if you were,nt used to handling it
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Z faces
Dec 18, 2013 11:37:48 GMT -5
Post by John on Dec 18, 2013 11:37:48 GMT -5
I might add for those that don't know, Polar Ajax is a powerful explosive, only it's not allowed to be used in coal or ripping lips. Polar ajax was made by ici Driftex was made by ecp , both were P1 types of explosives only allowed to be used in solid stone ,cross mesures drifts and shaft sinking and only where no coal was present and firedamp readings we,re below a certain level . it was strong stuff and could give you a throbbing headache if you were,nt used to handling it I think after that episode Gadge, the shotfirer charged all the holes himself...LOL
Back then, he just made the "primer" shot and tamped it in the shothole and let the rippers and stablehole men place the rest of the sticks of powder in the holes themselves, then they stemmed them, he just made sure everything was to his liking and connected the det wires together. Different at Cotgrave, the Shotfirers played by the book.
Makes me wonder how much powder was left underground, probably tons of the stuff..
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Z faces
Dec 18, 2013 14:51:35 GMT -5
Post by tygwyn on Dec 18, 2013 14:51:35 GMT -5
Strange way to prime a shothole,ramming primer in first,then leaving others ram up the powder .
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Z faces
Dec 18, 2013 15:34:49 GMT -5
Post by John on Dec 18, 2013 15:34:49 GMT -5
Strange way to prime a shothole,ramming primer in first,then leaving others ram up the powder . They sometimes used to give the primed charge to one of the men to ram in the shothole Jim...ALL illegal at that time, not sure these days, probably still illegal...Remember, this was back in the 1960's, and the faces were on the old power loader agreement, "aka" contract faces... Like I stated, didn't happen at Cotgrave, men weren't allowed to handle powder..
I've given shotfirers a hand charging headings up when I was working at BG's Marblaegis Mine, helped pass the time on when on face duty...Not much else to do... One of the shotfirers was caught one day with a ciggie in his mouth charging a heading up, by the Mine Manager, he went ballistic at him....As soon as he was out the way, the shotfirer lit up again and carried on charging the heading... I used to smoke back then, and it always seemed odd being able to smoke underground, having been brought up in coal..
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Z faces
Dec 18, 2013 15:42:45 GMT -5
Post by John on Dec 18, 2013 15:42:45 GMT -5
Here's another one Jim.....I was on nights at Marblaegis, we only had one elec, one fitter and one diesel fitter on nights..Usually we were on breakdown coverage only, very little work was ever left the night shift maintenance crew. mine foreman came in the elec shop, he hated driving, asked me to drive him outside in the Landrover to pick up some boxes of powder...I wasn't authorized to drive any vehicle carrying explosives!!! Only for general duties and manriding... Anyway, stopped outside the powder mag, loaded a few pounds of boxes of powder on the back, then the foreman said stop at the det magazine..Gave him a hand to load a couple of leather det cases with dets, he booked everything out and locked up and we set off back underground. I said "Jack, isn't it illegal to carry powder AND dets on the same vehicle"?? "Don't worry John, if anything happens, we won't be around to answer for the consequences" I just burst out laughing.
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Z faces
Dec 18, 2013 17:36:51 GMT -5
Post by tygwyn on Dec 18, 2013 17:36:51 GMT -5
What i was meaning as strange was,to ram in the primer,then the stable boy`s to ram the powder later,much better to ram all together to avoid getting coal between pill`s.
I worked in 10 different Smallmines,only one that the fireman loaded and fired shotholes,others you loaded and fired your own,illegal,but that was the norm if you wanted to work and earn money.
Illegal for us to handle dets,but allowed to carry powder,not sure what the allocated legal weight was,but on average we carried 30 small pills when working the small seams.
Aquaspex was the mostly used powder we had in the Smallmines.
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Z faces
Dec 18, 2013 17:59:34 GMT -5
Post by John on Dec 18, 2013 17:59:34 GMT -5
The only two tradenames I recall now were Polar Ajax and triminite, triminite (sp) was what they used in gypsum, more a quarrying powder. They also started using ANFO when I worked at BG, that powder is pumped in from a "kettle" mounted on a tractor, very powerful explosive when used in shot holes.. A primer shot was added to the shot hole prior to pumping the ANFO in... ANFO came as premixed in 50lb boxes..
I have no idea what powder we used at Boulby, didn't take much notice, usually too busy when I was a face electrician as I had two districts to cover.
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Z faces
Dec 18, 2013 18:24:40 GMT -5
Post by tygwyn on Dec 18, 2013 18:24:40 GMT -5
Minispex was another powder we sometimes had,smokey stuff,if i remember rightly it was in a Pink and White paper,and the powder was White,another in Green and White paper ,white powder again,cannot remember the name,smokey again.
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Z faces
Dec 19, 2013 17:22:33 GMT -5
Post by drgjs on Dec 19, 2013 17:22:33 GMT -5
Another time, another world. All (virtually) is Ammonium Nitrate based now. ANFO first (AN + 6% Fuel oil (diesel)), later emulsions (AN solutions, usually gassed to consistency of mayo of vaseline), then mixes (heavy anfo, doped emulsions), watergels (disolved AN, with a little aluminium in for good measure). detonation cord and shock tubes. electronic dets. My opening remarks were "whats changed in meantime...not much" - how wrong! I've never even heard of the stuff you mention - and I am an expert!
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Z faces
Dec 19, 2013 17:43:55 GMT -5
Post by tygwyn on Dec 19, 2013 17:43:55 GMT -5
Ammonia Nitrate= Fertilizer
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Z faces
Dec 19, 2013 18:07:47 GMT -5
Post by Wheldale on Dec 19, 2013 18:07:47 GMT -5
Years ago if a quarry ran out of ANFO the quarry manager would often go to a local farmer and buy his fertilizer! You don't have to get the mix with diesel spot on for it to be explosive. That's one reason why in Ireland you couldn't buy fertilizer pellets. ANFO is also good if you get a miss-fire as it dissolves in water. If you came across a miss-fire you would just remove the stemming and put a hose pipe in the shot hole, no messing about with an spayipan to get the explosives out!
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Z faces
Dec 19, 2013 20:33:16 GMT -5
Post by tygwyn on Dec 19, 2013 20:33:16 GMT -5
Exactly Wheldale, Its a practice going back many years,strange the Dr has`nt heard about it.
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Z faces
Dec 20, 2013 3:56:31 GMT -5
Post by drgjs on Dec 20, 2013 3:56:31 GMT -5
Ammonium Nitrate = fertilizer but not detonable. Ammonium Nitrate + "tricks" = explosives of many sorts and power. The issues Wheldale raises about Ireland and now factors globally of course due to other threats, so one has to be a little careful. And what would the explosives companies say - fertilizer grade AN prills are no good for explosives, so they say. The trouble with water and ANFO is that it is a two edged sword - in open casts coal [overburden] mining today we are talking hundreds of holes at a time, say 250mm diameter and tens of meters deep. Misfires can be a disaster and costs enormously - try washing that out with a hose. But if the ground itself is wet or it rains, then ANFO will misfire all over the place. Thus the advent of sticky emulsions - waterproofing - was the next game changer.
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Z faces
Dec 20, 2013 4:49:07 GMT -5
Post by dazbt on Dec 20, 2013 4:49:07 GMT -5
I know nothing about explosives (before I'm told I don't) but what I do know is that I had a mate (now long gone) who worked originally in the copper mines at Avoca in S.Ireland and later in the nearby fertilizer factory at Arklow during the 1960s. He knew a thing or two about using Ammonium Nitrate to fell trees and clear errant stone boulders locally. He told me that even the Calcium Carbonate mixed Ammonium Nitrate that the factory produced could be used even though the stuff they produced was made into pellet or large granule form and supposed to be non-explosive. The granules or pellets were simply crushed and used with diesel in exactly the same as Ammonium Nitrate explosives.
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Z faces
Dec 20, 2013 15:42:17 GMT -5
Post by shropshirebloke on Dec 20, 2013 15:42:17 GMT -5
For many years bags of "Nitrochalk" fertiliser carried no proper warning about the dangers of storing it near to diesel tanks, to avoid flagging up its potential as an explosive. As a result there were quite a few farm fires (the mixture wouldn't explode without a detonator but would burn like mad and was near impossible to extinguish).
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Z faces
Dec 20, 2013 15:58:31 GMT -5
Post by drgjs on Dec 20, 2013 15:58:31 GMT -5
dazbt, ssh. we are not meant to know that! in fact those holes in the narrow reefs in SA are pneumatically loaded with pulverized anfo. I have pictures of the poor buggers with it all over them, faces and all. horrible. there are few explosive accidents per se. Some say they used to have much more success with dynamite and tamping the hole with chewed cardboard in years past. In zimbabwe, they use to throw the prills against rock to break them up I have also heard.
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Z faces
Dec 21, 2013 6:53:20 GMT -5
Post by dazbt on Dec 21, 2013 6:53:20 GMT -5
Are there any African gold mines where mechanised extraction is used i.e. machine cut?
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Z faces
Dec 21, 2013 7:46:07 GMT -5
Post by Wheldale on Dec 21, 2013 7:46:07 GMT -5
Some mines use drill rigs to bore and blast with LHD's to move the ore but that's about as mechanical as it gets. It all depends on the geology. I saw a stope once were the reef was 8 meters thick but the mine still used the tradition method of drilling with an jack hammer and air leg.
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Z faces
Dec 21, 2013 12:01:25 GMT -5
Post by drgjs on Dec 21, 2013 12:01:25 GMT -5
Are there any African gold mines where mechanised extraction is used i.e. machine cut? The narrow reefs are gold and platinum and the small, cramped spaces make it impossible to supervise, let alone mechanise. Diamonds and other gemstones are also mined in Africa of course. Kimberlite is the diamond bearing rock. Drill and blast again and then the broken rock is processed to try and get the diamonds out - all while trying not to damaging them! Chinese firms own a lot of mines elsewhere in Africa. If anyone is mechanized in Africa, I would presume it would be the Chinese run mines?
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Z faces
Dec 21, 2013 12:39:32 GMT -5
Post by Wheldale on Dec 21, 2013 12:39:32 GMT -5
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Z faces
Dec 21, 2013 15:12:01 GMT -5
Post by dazbt on Dec 21, 2013 15:12:01 GMT -5
Forty years (or so) ago Anderson Mavor developed a cutting machine for use in the Gold Mines of Africa, which I understood was intended to cut only the narrow bands of gold bearing ore I believe this was banding of up to a maximum thickness of around ten inches in height. I know that this type of machine was in use for at least two years but from memory I never heard that it was a success that led to other similar machines being produced. The basic concept was of a self advancing cutter that used flat faced scraper tooling that reciprocated in a similar way to a shaping machine, i.e. traversed left to right in scraping cut and then in rapid return mode came back with the cutting tool 'collapsed'. The rest of this principle I would have to guess at, was it likely that this application used to undercut and destress the stope whilst separating the gold bearing 'reef' from the overburden that was subsequently fired out ? ........ I've no idea. What I have heard from my ex-Anderson mates is that Caterpillar are spending a fair amount of time, money and effort in developing cutting machine concepts that will be applied to "thin seam" hard rock extraction that is expected to include African gold mining. I can't imagine, off the top of my head, this type of development being too much of a threat to the people who's livelihood depends on the application of underground explosives ........... but on the other hand, the same thing might have said pre the coal mining mechanisation age.
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Z faces
Dec 21, 2013 15:49:11 GMT -5
Post by Wheldale on Dec 21, 2013 15:49:11 GMT -5
I've got a book about a Cornish tin mine, I think it's Geevor mine, I'll have to dig it out. Anyway, it shows a picture of a Dosco road header underground that was tested underground for tunneling. It was a complete failure. With gold mining I've been in stopes were the reef has been about a cm thick, another stope 8 meters thick so I would imagine it would be very challenging to construct a machine were the reef thickness can vary from one part of the mine to another. It will be interesting if the caterpillar Boyes come up with a machine to mechanise the stopes.
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Z faces
Dec 21, 2013 16:40:39 GMT -5
Post by dazbt on Dec 21, 2013 16:40:39 GMT -5
Gave Catapillar gold mining a Google and came up with this; www.im-mining.com/2012/09/22/new-hard-rock-cutting-technology-from-cat/I found the last paragraph interesting even though it didn't divulge much detail. The early Dosco road headers were great machines when applied to little more than coal mudstone cover but almost useless in tougher stuff, I seem to recall that such as the Anderson RH25, Thyssen Titan and Sandvik Alpina machines were hardier animals that stood up much better to sandstone, Dolomite and such, or maybe even worse.
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Z faces
Dec 21, 2013 16:56:57 GMT -5
via mobile
Post by Wheldale on Dec 21, 2013 16:56:57 GMT -5
That CAT machine looks a beast!
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Z faces
Dec 21, 2013 17:26:53 GMT -5
Post by John on Dec 21, 2013 17:26:53 GMT -5
Gave Catapillar gold mining a Google and came up with this; www.im-mining.com/2012/09/22/new-hard-rock-cutting-technology-from-cat/I found the last paragraph interesting even though it didn't divulge much detail. The early Dosco road headers were great machines when applied to little more than coal mudstone cover but almost useless in tougher stuff, I seem to recall that such as the Anderson RH25, Thyssen Titan and Sandvik Alpina machines were hardier animals that stood up much better to sandstone, Dolomite and such, or maybe even worse. A Dosco Mk1A was used briefly at Wongawilli Colliery, NSW, when I was working there, management seemed to think it would fair better than a Heliminer 120H in dykes...Guess what won.....Although even the HM120H needed extensive repairs, so management decided not to allow anymore headings driven through dykes......LOL
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Z faces
Dec 21, 2013 17:28:00 GMT -5
Post by John on Dec 21, 2013 17:28:00 GMT -5
Minispex was another powder we sometimes had,smokey stuff,if i remember rightly it was in a Pink and White paper,and the powder was White,another in Green and White paper ,white powder again,cannot remember the name,smokey again. Nahhhh...LOL I won't go there, but the colours......LOL
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Z faces
Dec 21, 2013 17:31:11 GMT -5
Post by John on Dec 21, 2013 17:31:11 GMT -5
That CAT machine looks a beast! Cat own what used to be Anderson Strathclyde, through a few other companies along the way...
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Z faces
Dec 24, 2013 13:00:03 GMT -5
Post by caiman on Dec 24, 2013 13:00:03 GMT -5
Back to Z faces - I have worked on these at Shireoaks as a student summer miner. Basically, one roadway was re-used after an advance longwall for an adjacent retreat longwall. Normally the supply side as the conditions tended to be too bad for the loader and belt. It was an interesting idea that didn't work in the reality of poor ground conditions.
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Z faces
Nov 9, 2014 14:09:12 GMT -5
Post by dibber on Nov 9, 2014 14:09:12 GMT -5
back to Z faces, s43's at manvers used s35's T/G as its T/G, and a new main gate & face line was driven to give a retreat panel of 1000m with a face length of 220m. every 10m an access tunnel was driven, about 3 to 4 m long from the old T/G into the stub end of the face, about 1.3m high by 1.5m wide, as the face retreated then another tunnel was dug to the face so allowing ventilation and supplies to enter the face at the tail end
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Z faces
Sept 2, 2018 16:00:39 GMT -5
Post by stuntman on Sept 2, 2018 16:00:39 GMT -5
Anyone ever worked or been on a Z face? I read that Thurcroft had one. Basically its a cross between an advancing and a retreating face. You have two parallel roads which are linked by one road. The face uses this linked road as a gate like in retreat mining. At the other end of the face the return gate is formed like it would be on an advancing face with a stable hole etc.. Theres a link here to a Z face at Thurcroft, the mine plan at the bottom shows the lay out of this one. thurcroftcolliery.weebly.com/miscellaneous.htmlAll the faces except the first in our 3/4 seam were operated in the Z system. Cheaper as one gate is resused so only one gate has to be driven per face. However we decided on this system to minimize surface subcidence
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