PSN-L Email List Message

Subject: RE: Hello
From: "Ron Westfall" westfall@........
Date: Thu, 26 Jul 2001 13:34:09 -0700


The "governing" authority for mines is the State Fire Marshall...and the
laws governing mining are full of loop holes at best.  The immediate problem
is that the mine self-monitors their blasting activities through a
subcontractor.  First, many in the community do not believe that the mine
always makes aware the State when they are to blast and second, we do not
believe the reported results are accurate.


If all you want to do is verify that the monitoring company is reporting all
of the blasts that take place, you could set up your
own recording seismograph fairly inexpensively.  I would suggest a geophone,
some of Larry Cochrane's electronics, and
a PC.  Larry sell electronics and geophones through his web page at
www.seismicnet.com.  Most of us are using his
electronics.  The courts would probably accept your evidence for the
occurrence of blasts.

Keep in mind that if you try to set up your own equipment, you will record
all sorts of local cultural noise (e.g. cars and
trucks passing by on nearby roads) in addition to blasts.  Situating the
seismograph away from such noise will reduce
the clutter.  Even so, you will get some non-blast events.  Through
correlation with the blasts that are reported by the
monitoring company, you should learn how to distinguish between blast and
non-blast events.

If you need to record the strength and any other characteristics of the
blasts such that they could be used in court, I
agree with Doug that you would be better to get professional help.  By
changing the gain on a seismometer pre-amp, it
is easy to create as small or large a trace as you want for a given event.
It would be difficult for an amateur to calibrate
the seismometer and maintain the calibration over a period of time to stand
up in court under expert scrutiny.

Ron








The "governing" authority for mines is = the State=20 Fire Marshall...and the laws governing mining are full of loop holes at=20 best.  The immediate problem is that the mine self-monitors their = blasting=20 activities through a subcontractor.  First, many in the community = do not=20 believe that the mine always makes aware the State when they are to = blast=20 and second, we do not believe the reported results are = accurate.
 
If all you = want to do is=20 verify that the monitoring company is reporting all of the blasts that = take=20 place, you could set up your
own = recording=20 seismograph fairly inexpensively.  I would suggest a geophone, some = of=20 Larry Cochrane's electronics, and
a PC.  = Larry sell=20 electronics and geophones through his web page at www.seismicnet.com.  Most of = us are=20 using his
electronics.  The=20 courts would probably accept your evidence for the occurrence of=20 blasts.
 
Keep in mind = that if you=20 try to set up your own equipment, you will record all sorts of local = cultural=20 noise (e.g. cars and
trucks = passing by on=20 nearby roads) in addition to blasts.  Situating the seismograph = away from=20 such noise will reduce
the = clutter.  Even=20 so, you will get some non-blast events.  Through correlation with = the=20 blasts that are reported by the
monitoring = company, you=20 should learn how to distinguish between blast and non-blast=20 events.
 
If you need to record the strength and any=20 other characteristics of the blasts such that they could be used in = court,=20 I
agree=20 with Doug that you would be better to get professional help.  By = changing=20 the gain on a seismometer pre-amp, it
is=20 easy to create as small or large a trace as you want for a given = event.  It=20 would be difficult for an amateur to calibrate
the=20 seismometer and maintain the calibration over a period of time to stand = up in=20 court under expert scrutiny.
 
Ron
 

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Larry Cochrane <cochrane@..............>