31 Jan 96
COMPARISON OF COSTS FOR SCAPS VERSUS CONVENTIONAL DRILLING
1. Current experience has shown that daily costs to operate the
SCAPS may be higher than operation of a hollow stem auger. The
following comparison will show, however, that because of the
unique capabilities of the SCAPS, total project costs will
probably still be less than if conventional drilling techniques
alone are used. The costs used for this illustration are based
on CEMRK drill crew and SCAPS average daily rates. Assumptions
are the same as those shown on page B-3: working days do not
include mob/demob but mob/demob costs are averaged in total cost.
Resistivity pushes, prepushes and pushes to obtain soil samples
have not been accounted for in this comparison. Twenty-five LIF
pushes and eleven wells are installed during an average project.
a. An average 25 foot deep LIF direct push boring (from
table on B-3) is equivalent to a 25 foot deep auger boring made
to collect five soil samples for laboratory analysis.
(1) two of these 25-foot-deep borings can be drilled and
sampled in a day
(2) includes set up, drilling, sampling, sample
preservation, decontamination, and backfilling
25 borings/2 a day = 12.5 days
b. An average 21 foot deep well point installed in sand by
direct push is equivalent to the same depth well installed
through hollow stem augers (the most frequently used method of
well installation on HTRW sites).
(1) Each well installed through hollow stems will take
approximately 12 hours to set up, drill, set well, decon, and
11 wells x 12 hours = 132 hours/8 hours = 16.5 days