The Hawaiian gazette., 1904-11-22


continuing ihf tunnel would rpoh hoa
come trnhihitto Progress now. owe
us t1 tha Improved facilities De- HH
r rld pt whom thr WORK was hrsf finft-
rI Ne1ut miir ia Travelled u one
round tf.r nf Hn ore tur
Tha mrHuyinr photographs VIII
plyu iho reader nn idca NJ the nature
uf ih. uprrntuua. both un tlu surfHro
ana underground.
Tho flash light picture shows tho COM
ditlon of the face ~ the tunnel 20gO feet
underground Tho writer claims 90 be
well posted on modern mining prnc-
tlcos. but VIII be very grateful 10 any
one who viii give him hint how TO
load round Of drill holes from each
of which the water Is bursting under
about 400 pounds pressure.
This enterprise can now be safely
rated az a valuable and constantly in
creasinP nsset Of the Pioneer Mil Com
pany, Ltd.
The cliffs through which these tun-
neling operations are conducted are
composed Of solid hard. water-bearing
rock, every foot Of advance being gain
ed by much drilling and blasting. There
is very little evidence here of layers
and stratifications, the formation can
best be described as a solid mass of
basalt. 1t has been demonstrated by
operations here that success will not
follow the blind driving Of tunnels,
even in such favorable localities as this.
There are certain principles that must
be understood, together with a knowl
edge of the simple laws that govern
water flows.
There Is a system which, II followed,
will prevent costly mistakes and lead
the operator to success.
WATER SHEDS.
The writer feels called upon to dis
cuss the question of water sheds as
some confusion exists in applying this
term to conditions in Hawaii.
on these islands the greater part of
the rainfall sinks directly into the
earth, and after a longer or shorter
subterranean course comes out again to
add to the flowing streams-otherwise
maintained by their respective water
sheds-or continues underground until
1t reaches its static level. Where a
stream has a minimum flow so large
that it cannot be accounted for by the
area and productiveness of its water
shed, it points conclusively to the fact
being fed by subterranean water
courses. (Plate 80 For instance, the
streams radiating from the West Maui
mountains that have a strong constant
minimum flow owe it to the stability
of these underground supplies whose
sources are unquestionably in great
many cases far remote. The valleys
or gorges of these streams have eX-
posed and intercepted many under
ground flows. By tunnelling the same
result is reached. 1t would be impossi-
BILE, by a tunnel system, to exploit
as large an area as is exposed by
stream erosion, but this is not neces-
sary nor desirable. The geological con-
ditions that govern the concentration
and flow of these underground streams
can, in a great many cases, be so ac-
curately determined that the desirable
points can be reached by proper sys-
TEN of tunnels, without any unneces-
sary and wasteful ramifcations Where
it is known that streams are being
partly maintained from subterranean
sources, it can be accepted that a still
further gain can be made by tunnel
ling. The Kauaula tunnel has develop
ed a far greater flow of water than is
shown in any of the streams on the lee
side of Maui.
CONTINUITY OF FLOW.
The writer has spoken with some
confidence of being able to locate under
certain conditions, underground veins
of water but is not willing to guaran-
tee the stability of these flows. Wnen
it comes to determining whether the
flow developed will be constant moth
ing but experience can act as guide.
Several springs on the Ulupalakua
ranch, developed upon the advice of the
writer during the last three years,
have all continued to give an increased
flow. The flow at Polipoli has been
augmented and holds up strongly. The
early in 1901 and the II. c. & s Co. tun-
mel, both in lao Valley, finished year
later, continue to hold up their usual
flow, even during the severest
droughts
Tunnelling at Kauaula has been con-
stantly in progress for over two years,
and in that time there has probably
flowed out of the tunnel five billion
gallons of water, and the flow is con-
stantly increasing. 1t does not appear
that there is any danger of the tunnel
running dry. Care must be taken. how
ever, not TO overtaX the underground
storage. Too much tunnelling must
not be done in limited area. There
are n great many other examples of
successful tunnelling on these islands. |
\ great many failures have also to be |
recorded. AS near as the writer can |
learn these failures have not been
caused by the draining of under
ground supplies. They have been caus-
ed mainly by exploiting in unfavorable
localities, or i'm not intelligently pros
pecting In favorable fields. Some |
streams have been destroyed by bum |
Cling work, II must be remembered |
that sometimes very slight imper- |
vlous layer Il holding the water; II |
I his ia NHgfFpN tho tl,Kr t,Ru.F D.. I,sf