drilling granite

Hi guys,
I need to drill granite rocks on vertical cliff for a project of sky walk as 10''x7'' inch to accommodate 90 beams as supporting structure .. on the group we have different idea on how to start project like that but we would like also ear from somebody that has similar experience how to drill in this unusual position and which tools better to use (cliff is 800mt high ) I was considering to use Jet Stick for drilling horizontal wholes on the block ,did u think my idea is technically possible ?
Tks to all

 

[miningman]

Youre going to have to provide a lot more detail as to what it is you are trying to do. I could drill this off quite easily if you want something 30-50 metres below the top surface exposure but what exactly does your required end product need to look like.... youve got some seriously fractured rock there , I would guess the fractures extend at least 20 metres into the face.... are you trying to remove all unstable rock or are you trying to do something cute within the unstable rock.

 

[105520]

tks ,we are still investigate on stability of top part..in short;plan is to drill under the top cracks,anchoring concrete beam 3.5 inch out to create glass path.. point is how to position heavy equipment and how "to hang" the operator on cliff..from here the idea to use torch to drill granite.Remove the top part is not possible due to size of rock may we considering an anchor or rod bolt .. around there there are not visible fragmentation all rock looking quite stable..

 

[IRstuff]

Why is an EE doing this evaluation? Is this for school?
Why haven't you contacted the people that have already built an identical structure:

http://www.grandcanyonskywalk.com/about-the-skywalk/engineering/

Pay particular attention to the video, including the cost.

TTFN

FAQ731-376
Chinese prisoner wins Nobel Peace Prize

 

[cvg]

this is means and methods for a driller to consider. find a good driller and let them decide how to get the dril into position. suggest that a good geotech should be on the team to advise you of these things

 

[105520]

I'm trying to be short on my request but if somebody want details I'll supply more.. "I'm helping an NGO in a Skywalk feasibility study ,this project has humanitarian target to improve kids health in African villages and will target tourist as generator ."As u understand our finance(we cannot looking at grand canyon ! too big for us..) are limited so we cannot use international company to realize this dream, we'll use small local company on contract basis ..We have call for a geotech study but we would like as I say avoid unnecessary test/jobs may be performed just to increase the bill,we do not want trash money with unnecessary jobs ..
for this reasons we would like ear from somebody that has specific knowledge or has made similar drilling experience; if u can pls forward you idea on it..

the 90 beams as supporting structure protrude 30" outside rock ..

Question was ue to unusual drilling position which tools better to use ? jack hammer (with vibrations may we penalizing rocks stability) or diamonds tools ?(mind that front cliff is 2500 ft high ) I was suggesting to use Jet Stick torch for drilling horizontal wholes on the block ,did u think my idea is crazy or technically possible?
Stability of top stone ; with no sign of fresh cracks on granite ,no sign of spallation ,no sign of slope instability what test we must do to reach safety level ?
I'm understand that identifying the stability is not possible by pics, but grouting (as suggested from a company..) a massive blocs like that has "millennium" of water erosion on the crack around is something worthwhile in the real world ?
hope now is more clear
Tks to all

 

[IRstuff]

It wasn't just about the company; it was about the basic approach. I just don't think a face based cantilever will work. Had you looked at the video, the anchors aretens of feet into the rock

TTFN

FAQ731-376
Chinese prisoner wins Nobel Peace Prize

 

[miningman]

IRstuff is right. If you really are an electrical engineer working in the third world, dont just walk away from further involvement in this project.... run away. Despite what you have suggested, the stability...... or lack thereof is clearly evident from your photo. And I can gurantee there is no way to economically stabilise this rock mass if you "just" want to construct a structure below the obvious areas of weakness. I can almost gurantee that significant planes of weakness exist 20-30 metres into the rock face. If you insist on persuing this, start investigating blasting all the loose rock into the canynon below, THEN start your geotechnical and structural analyises.

If you want some ideas on how to proceed, ckeck out how Mount Rushmore was developed in the 1930/ 1940s. That is how I would approach this project, but lets not fool ourselves, dozens of men lost their lives on Mount Rushmore, and today's policies and procedures will not change that....... you will have to accept that fatalaties are likely if you proceed.

 

[IRstuff]

I was in line at Costco earlier, so had to skimp on the posting. A 2.5" screen just doesn't cut it for a keyboard ;-)

The Grand Canyon Skywalk video is quite instructive; the moment is countered by the entire mass of the cliff, and everything related to the rock is in compression, which is what's most desirable. The walkway isn't even in contact with the rock; it's completely supported only by the pilings, and the pilings look to be close to 100 ftinto the rock, and set back from the edge from about 5 ft to about 40 ft. And, this is on fairly solid sedimentary rock.

The factsheet has lots of good details:

http://www.grandcanyonskywalk.com/wp-content/uploads/2011/08/Skywalk-Facts-updated.pdf

Note the load capacity of the pilings is 71 million pounds, yet the walkway itself is only about a million. This is just not something that can be done with glued-in metal rod anchors from the front face. Note particularly the year and a half of drilling.

This is not something to be done by amateurs. You're going to need a raft of specialists, probably including at least a handful of geo specialists and they'llave to argue amongst themselves until a consensus is achieved. ONLY THEN, should you even contemplate what the implementation should be. Your cart is drastically ahead of the horse; worrying about how to drill for anything is absurdly premature.

TTFN

FAQ731-376
Chinese prisoner wins Nobel Peace Prize

 

[105520]

Tks guys for ur opinions & suggestions....
just to be extra clear our idea was not to built a cantilever similar of grand canyon ! too expensive too technological ...our starting idea come from this place Tianmen Mountain

http://recommends4u.blogspot.com/

where very similar project has been done in environment almost identical to one we have...simple 30" protruded face beam anchored on granite cliff ,we even contact the Chinese park office for info and the answer was simple : "you don't need to know so many things..this project is just normal building project that can be done around the world from any qualify building company.." !! looking at the rudimentary structure they prepare leave me breathless but project has been done there..

 

[IRstuff]

It would have saved LOTS of time had you posted that link first.
I don't see anything that implies a Jet Stik is appropriate for drilling holes.

TTFN
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[Debaser]

...and will target tourist as generator.

We have call for a geotech study but we would like as I say avoid unnecessary test/jobs may be performed just to increase the bill,we do not want trash money with unnecessary jobs..

I usually smile to myself when I read some of these questions and the first answer is along the lines of 'get a professional to do this', but in this case, where you hope to make money long term from tourists, their safety and thereby your (ie the locales) reputation has to be paramount, and as such I don't see any test of stability being 'unnecessary' or 'trashed money'.