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Date: | Thu, 9 Dec 1999 10:21:50 -0500 |
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>Date: Wed, 8 Dec 1999 14:22:43 -0500
>From: Lynn Pietak <[log in to unmask]>
>Subject: No subject given
>
>Hi-
>
>I'm preparing a work plan for Phase II testing at an urban HAZMAT (former
>manufactured gas plant) site and am looking for ideas on how to trench and
>examine deposits which could go as deep as 10-20 ft. Given conditions on the
>site, I am not permitted to step-trench or to use sloping. I'm considering
>the
>use of video equipment so we don't have to get into the trenches and welcome
>any
>thoughts or experiences on that or various types of shoring, box trenching,
>etc.
> Thanks--
>
Lynn-
We've used video cameras on long cables with attached lighting to investigate deeply buried deposits, however, from my experience the resolution is not great and you are furthermore looking at a very small window so its a useful technique only for examinig small areas - not long profiles. I would recommend taking your trench down in controlled cuts (say 6" or so each), examining the soil on the surface and recording the stratigraphy from above ground as you go. You would probably want to use a transit and stadia for your depth control and have an operator who is competent operating a machine on level shallow cuts - folks who do foundation work in the housing industry are a good bet. Given your potential depth you should also move the spoil pile way away from the side of the trench or else risk a collapse which could effect folks on the surface. I would be more concerned about the HAZMAT issues than the depth - with a trench of that potential depth you are not going to know what is being pulled up until
Joe Joseph
the opinions expressed in this posting are my own and do not necessarily reflect the views of my company or any other organization with which I am associated.
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