There is a good thread about modern rock removal to make rights of way hiding in this thread…
http://www.trains.com/TRC/CS/forums/1192643/ShowPost.aspx
It has set me thinking about the very good point made in the OP and my own questions.
Can anyone lighten our darkness on the subject of what blasted cuts end up looking like please?
TIA
[8D]
The most prominent feature is the drill shafts. A series of parallel shafts are drilled into the rock along the line of the face to be blasted. They’re filled with explosives, and then somebody yells, “Fire in the hole!” and the explosives are detonated. (At least I hope they still yell that. It’s such a colorful phrase. Does anyone know?) The rock face then explodes outward, leaving a reasonably flat face with half of the explosive shafts still showing. There will still be fine-scale rock structure, but usually no ledges or outcroppings will remain on the face. The remaining half-shafts will be pretty much vertical, straight down across the rock face.
After the rocks tumble down and the dust settles, Wile E. Coyote will crawl out from under the pile, stagger around a bit, and then be run over by a bulldozer.
Here are two attempts to do the blasted sections the North shore of Superior. The first uses rock castings.
The second is carved dirrectly in the foam. My son suggests that the drill marks could be more pronounced.
BEEP!! BEEP!! [(-D][(-D]
If you are modeling some of the tougher rock (like the disguised ceramic armor used as bedrock in parts of Da Bronx) a coarse-toothed grooming comb (teeth 3/8" or so apart) drawn up the semi-set plaster face should do a good job of simulating the un-displaced parts of the shot holes.
Chuck (modeling Central Japan in September, 1964)
Really like the pics. I remember being up along the North Shore when they were doing some of the cutting. The second is a great picture. Looks very real.
Beasley I believe they are called bore holes, not drill shafts. I will check with my son and report back if they still shout “Fire in the hole.” He works for Dyno in West Virginia, usually at a coal mine where they do a daily shot. Rock also flys as well as tumbles. That is why blasting mats are used to keep the fly rock down. It all depends on the size of the shot. The minimum safe distance for a half pound charge is 2700 feet, says so in the woodchuck manual FM5-34.
Essayons Eh!
How did he get started? That was a type of job that I spent 3 yrs, trying to find training for.
Greg H.: My son spent 7 plus years in the U S Army as a Combat Engineer. He did extensive demolitions in Iraq destroying Iraqi munitions. You can’t get that kind of experience in a school. Working in a coal mine doing the daily blasting is a lot safer than what he saw while in Iraq. Once and a while he does get out on a road job, but usually he works at the same mine.
I heard back from my son on proper blasting procedure:
We said it in the army and for Dyno we get on the cb
and say “we now have fire fire fire in the hole” and
then you scream “fire in the hole” before you pull the
trigger.
Justin
— Ed Cooper wrote:
Justin: Do you guys still shout, “Fire in the hole”,
before each blast. Someone on another forum was asking and I
said I would find out. We did it for every shot we did in the
engineers back in my day.DAD
I think your attempts to standardize the drill holes probably have a date consideration. Until the advent of gang drills the hole pattern would be more random. One look at pictures of the Central Pacific blasting in the Sierras on Donner pas should confirm this. If you are modeling a railroad that has been in business for some time and I would guess prior to WW2 I don’t think the uniform drilling fits the era. Post WW2 it is probably correct.
Cool, thanks for checking.
Do you have a link to pics of the CP blasting in the Sierras?
Post 1880’s powered drilling equipment starts becoming common in the mining industry, and I would suspect that it would start being used to drill blasting holes for RR right of ways about the same time.
Blasting started to become a science in the 20’s and 30’s as dam construction in the west started to pick up, and continued post WW2 into the 50’s and 60’s, so I would expect to see shot holes to become more uniform and deeper through this time period.
Just about any book on the Central Pacific RR will concern itself with blasting in the Sierra’s; black powder and nitro pretty much defined the work.
Steam powered drills were available in 1868 when the Summit Tunnel was being cut, but for some reason the logistics just didn’t work out. The Central Pacific was the last railroad built using only human labor.
Cutting that Summit Tunnel would have been one big job. The granite in that area is extremely dense and difficult to work. It’s almost like flint, and sounds like broken glass when tossed in a pile. They resorted to nitro that had to be made on the spot because of it’s unstable nature, and still removed only 8" per day of rock despite working it from four different directions.
Some revisionists like to claim the Chinese work crews were treated like slaves in this endeavor, but the fact is the Chinese invented gunpowder, they knew it, and they loved blowing things up.
-rrick
You’re not kidding. If you’ve ever had a look at the actual construction sites, you’re just stunned by the level of skill it took to push a railroad over that ground. That job was done by highly skilled folks, not ignorant slaves!
If you haven’t read it yet, drop by your local library and pick up a copy of the late Stephen Ambrose’s “Nothing Like it in the World”, his history of building the transcontinental railroad. There’s a lot of good info on actual construction and some nice photo’s. Some of the statisics are mind boggling. The C.P. was using 500 kegs of blasting powder a day in "64. That’s more than was used in most major Civil War battles. Keep in mind that until the tracks met in '69 all C.P. supplies had to be shipped either around Cape Horn or unloaded in Panama, packed across to the Pacific side and reloaded.
I don’t have a web site of pics, but good reproductions of those old glass plate negative photos of the construction are worth looking for. The detail is fantastic…much better that what can be reproduced on the net. Many coffee table books on railroads or the American west reproduce some of them. If you can find a copy of the 3d sterographic photos, they’ll knock your socks off.
Jbb,
I’m not disputing that the powder was shipped around the Cape Horn, as I have no documentation one way or the other, but wouldn’t it have been more economical and more relyable delivery to have built a powder mill in Cali rather than ship it in from the east coast???
The placement and spacing of the blast bores depends on what sized muck you want to clean up after the shot, and where you want to pick it up from. The techniques vary widely depending on whether you are blasting a road cut, a quarry, the live end of an adit or drift, or raising a stope.
The blasts within a single shot are time delayed, to achieve the effect desired. Usually the earliest bores detonated are used to fracture the rock, then lifting charges move the fractured muck out to where it’s easy to haul away.
Another variable is whether you are able to get your drilling equipment up above the face you want to create. If not, or if it’s too expensive to do so, that rock will be face drilled and will show a different pattern of boreholes after the shot, if any boreholes are visible at all.
Yet another variable is the nature and quality of the rock being cut. Loose, soft, or friable rock, ash and some sedimentary silts may not show boreholes after the work is done, as the charges themselves obliterate traces of drilling.
In some situations, porous formations allow water to seep down behind the blasted face, and freeze and crack off the original face, obscuring the borehole patterns. Areas like these are often subject to frequent falling rock and steps are taken to reduce the objective danger of same, steel cables, mesh matting etc. During a trip to photograph the Heritage Golf Tournament back in the mid 80’s, a large face fractured and brought a section of rock down on a major NC freeway, near Asheville, if memory serves, several hundred yards long, 150-200 feet tall, and at least 50 feet thick. It closed a major tunnel, and four lanes of freeway traffic were diverted to a single lane dirt fire road which inspired less confidence than many of the 4WD only turn of the century mining roads I jeep on in Colorado. Obviously, no boreholes were left visible on the new road cut face.
In the Red Mountain Mining District of Colorado’s San Juan range, many mines still