Evening star., 1936-06-04

LIE IcScENhllOu, luCluulIlB pdtleIlIS
and employees He added. however,
that vastly greater amounts may be
required in emergencies and higher
pressure is needed for adequate fire
protection. The contract called for
a well yielding a minimum of 1886, 900
gallons a day.
For the last three years the hospital
has been getting its supply of water
from the District. Formerly it was
served by nine 4-inch wells drilled to
depths averaging about 400 feet. The
new well is drilled IS feet from one
Of the old wells, which no longer are
used.
Walled with gravel and drilled by
the hydraulic rotary process, the new
we'll is to cost the hospital approx
mately $4,000. Its 12-inch water
pipe is set in a 36-inch drilled hole,
lined with cement casing. Sixty tons
Of uniform filter gravel have been
filled in at the base, which has been
"underreamed."
The rotary drilling process employed
at ST. Elizabeth's is a relatively new
system. developed In the last genera
tion, principally for use in the Texas
oil fields. 1t uses water under pres
sure to loosen the earth material and
bring it to the top Of the hole.
"Cable" Drilling Tried.
The system used at Glenn Dale is
commonly described as percussion" or
cable" drilling. BY this method a
heavy drill bar or similar tool is alter
nately dropped and lifted in the man.
ner Of cold chisel to pound the rock
into fragments small enough to be
readily removed from the hole.
Chief advantage Of the rotary Sys-
tenn, according to engineers on the st.
Elizabeth job, is the fact that it en-
ables well-diggers to excavate near
the base Of the well and fill in the
extra space with gravel for prelim-
mary filtration purposes. Superiority
Of gravel-walled wells over those
drilled with the usual cable system
has been described in official bulletins
Of the Geological Survey. 1t is under
stood, however, that expense Of the
rotary drilling equipment prevents its
wide use.
After abandonment Of the Glenn
Dale well last week. Commissioner
Sultan announced negotiations have
been opened for construction of a
pipe line from reservoirs Of the Wash
ington Maryland Suburban Sanitary
Commission at Cheverly. Nd. to the
site OF the new tuberculosis Sanitar-
ium.
The pipe line, Commissioner Sultan
said, will extend about miles and
cost approximately $780, .0e0. Of which
$90, 900 would be paid by the District
Sees Need Of Pipe Line.
He was emphatic in stating that
the pipe line, as the only alternative
to the Glenn Dale well. would have 70
be constructed. More than 00,000
gallons will be needed daily when the
sanitarium is enlarged to care for
adult patients.
Although plenty of water was found
in the Glenn Dale well after rock core
was reached at depth of $50 feet,
Commissioner Sultan said, the samples
obtained indicate it would require
elaborate treatments to make it suit
able for human use. He mentioned
that Q slightly higher grade Of water
was found at about $50 feet, but it was
passed up in the hope that purer
grade could be found below.
The water is Objectionable, 1t Is
understood, because Of its large con-
tent OF silt No estimates have beer
made of the cost Of filtering the water
although Col. Sultan said such in
formation will be available when the
pipe line project plans are developed
and put forward for approval.
Private engineers have claimed thai
we'll capable of producing 250,00(
gallons per day and filtration plant
to reduce the silt could be constructed
for less than s75,ooo.