Bernard
Very interesting information. The significance of the powered drills can not
overstated. Thanks for your input - it will help.
Pat
----- Original Message -----
From: "Bernard Moore" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, March 17, 2003 5:28 PM
Subject: Re: Dynamite and mining production
> Dear Pat,
>
> The true effectiveness of dynamite explosives was dependent to a large
part
> on how fast a hole could be drilled to put it in! Therefore the history of
> drilling machines plays a significant role in the matter.
>
> Granted dynamite expls. had a significant impact simply by their VOD over
> blasting powder, but ground conditions and the expertise in their use
again
> plays a large part. Most serious books on Cornish mining will give you a
good
> idea as to the increase in ground breaking, but the main feature -
always -
> was the introduction of compressed air drilling machines (particularly in
> driveage).
>
> I feel, as a ballpark figure, a 30% increase was achieved with hand
drilling,
> and 70% by machine with driveage (average figures). Stoping is another
matter
> of course, but the numbers will be roughly similar.
>
> I hope this might be of some use. Regards, Bernard
>
>
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