Continued from: viewtopic.php?f=19&t=22175&start=15



Well, I guess I forgot to mention in my last post that if you're talking efficiency for long haulage in large quantities neither one takes the cake. Hence every high production UG coal mine in the US uses a belt system. Can't beat it.

These days, you're not gunna find (in the US) a new mine going in the ground with rail as it's primary production haulage (other than, almost specifically, poorly funded companies re-opening an old drift or anthracite mines). You had mentioned yourself that rubber tire must have become cheaper than rail, and I would agree that it is probably cheaper to produce LHDs and rubber tire equipment (especially diesel)... However, efficiency still plays a role in the development of the mine. Your thoughts on efficiency seem to be restricted to level ground. This is hardly ever the case in a modern rock mine tho, because they are no longer restricted to rail haulage. In the past, rock mines were driven in level drifts because this is what rail haulage allowed. Now, however, you can sink directly into a mountain side from the closest point to an ore body with a decline and easily load out the first 1000 feet or so with just a loader. If you're not sure what i mean, think of the mountain like a triangle. Then think of the ore body like a dot in the center of that triangle. If you were to draw the shortest line possible from the edge of the triangle to the dot, where would the line be? It would be from the center of a side of the triangle on an angle toward the dot. Not level. In mining, development is a killer. You need to get to where you need to be as quickly and cheaply as possible... and in development and production, dealing with rail and all the infrastructure it requires is no longer feasible. Even though rail can actually move material faster and in higher quantities than rubber tire equipment, you are extremely restricted by the issues in my last post and developmental issues in the mine itself. Face and initial development work is most efficient with rubber tire, and main haulage is most efficient with belts.

That being said, there are still a few shaft mines that use rail for production haulage for various reasons, but there aren't too many of them being sunk anymore!

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This ain't longwall... this is long hole!

Banks,

Thank you so much for your fascinating and informative post on this subject. It is very, very difficult for me to argue with you here because it is pretty obvious to me that you know what the heck you’re talking about!

In coal mines today, aren't most of the larger ones using those “continuous miners”? They can mine an awful lot of coal at once the way I understand. For that a conveyor belt would be an absolute necessity. I don’t see how rail could keep up with a continuous miner (c.m.). I don’t see how you could load cars fast enough to keep up with it. But when it comes to rubber-tired machines, I doubt they could either. In fact, a double tracked line with 20-car trains could probably keep up with a c.m. better than diesel powered LHD’s but would still be trumped by a good conveyor. Isn't that right?

I take your word for it that there are not many new mines that turn to rail but there might be a few, just not in the U.S. What is intended to be the largest underground mine in the world will be using modern rail haulage – in Polynesia. There might be other examples, too, I just don’t know where.

In hard rock mines, some of the older ones are sticking to rail – which you kinda suggested. The owner of one large western hard rock mine told me in no uncertain terms that "(The) Mine will continue its operation as a small rail operator. Why? It is proven (to) be the best economic system to succeed. Those who think otherwise have failed so far and have no record of success to champion their conduct." (Not sure what he meant in the last part of that last sentence but I think he was talking about some overbearing people who were trying hard to sell him something).

Unfortunately, I'd rather keep this quote anonymous. But consider this: Number one, the tracks are already there *AND* they are in relatively good condition.

Number two, he would have to widen all his drifts to accommodate diesel-powered LHD’s. This does not make economic sense - especially if you have to borrow the money to do it!

Your point about the level drifts in a tracked mine vs the inclines that rubber can tackle makes sense to me, too. If nothing else, you might end up doing away with an expensive and quite possibly hazardous elevator operation.

So, there are a lot of things to consider here. My uneducated guess is that going forward, we will see rail used less and less in modern mines. Will it disappear completely? Maybe not. Time will tell, I guess.

Regards,
Fred M. Cain

Hey Fred, check out this site. It has several fascinating plans on how people model the underground operations. Is is under "Mining" obviously. The Scrapbook also has several articles on how people model the mining. Standard and narrow gauge, above ground and under. I like the multilevel plans. http://www.carendt.com/microplans/index.html

as for the guy you were talking to running the mine out west theres probably specific circumstances that make rail the optimal choice.. which often happens.

However, a 20 car trip will never be efficient with a CM because you still need to get the coal off the miner and onto the main haulage........and that requires a shuttle car (rubber tire), and they are designed to unload onto a conveyor.

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This ain't longwall... this is long hole!