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What is the most energy-efficient way to crush the hardest bedrock on earth while assuming it is impossible to use the chain reaction energy from that bedrock?

How many energy is needed?

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closed as off-topic by jinawee, Brandon Enright, Waffle's Crazy Peanut, Dimensio1n0, John Rennie Dec 15 '13 at 18:40

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Depends. How long do you want it to take? –  Ignacio Vazquez-Abrams Jul 19 '12 at 23:38
    
@IgnacioVazquez-Abrams - For a terminator size robot punch his arm into the bedrock. –  Victor Jul 20 '12 at 0:11
    
Can you clarify your question. When you say "crush" do you mean break up into gravel? Are you thinking about tunneling through bedrock? –  John Rennie Jul 20 '12 at 8:34
    
@JohnRennie - yes –  Victor Jul 20 '12 at 15:44
    
Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise. –  Dimensio1n0 Dec 15 '13 at 15:07
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TBM's are the acceptable methods for creating tunnels. I think they will not be able to work if you have bedrock made out of diamonds and it may be extremely slow if it were made out of corrundum. Personally I have never heard of any bedrock made entirely out of one mineral, hence the term bed"rock". As far as crushing rock any rock crusher will do the job. Most I have seen and used feed vertically into a pair of vice-like jaws with one jaw moving back and forth. Softer rocks like limestone will be crushed down as small as you want it. Other rocks are submitted to a test called an LA ware where the sample is beat with 8 steel balls in a rotating drum. After a certain number of cycles you measure the amount of material lost. Believe it or not Quartzite used as railroad ballast disintegrates in an La ware test.

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I would think that a hardened hole saw approach would be most efficient. Bore a short distance into the rock with a self-augering hole saw the diameter of the desired tunnel and then impacting the center of the core to break out the center, remove the broken material and then take the next bore. Where is the sense of pulverizing the center material to dust like TBM's (tunnel boring machines) do, that's just wasting energy.

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