The Pacific commercial advertiser. [volume] (Honolulu, Hawaiian Islands) 1885-1921, 1904-11-22

By E. C. Miles.

of the operations, both on the surface
and underground.
The flash light picture shows the con-
dition of the face of the tunnel 1000 feet
underground. The writer claims to be
we'll posted on modern mining prac-
tees. but will be very grateful to 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 as a valuable and constantly in
creasing asset of the Pioneer Mill 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 qualifications, 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 knowl
edge of the simple laws that govern
water flows.
There is system which. if followed,
will prevent costly mistakes and lead
the operator to success.
WATER SHEDS.
The writer feels called upon to dis
cuss the question of wafer 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
it reaches it's static level. Where a
stream has minimum flow SO large
that it cannot be accounted for by the
area and productiveness of it's water
shed, it points conclusively to the fact
that the stream has intercepted and is
being fed by subterranean water
courses. (PIate 3d. For instance. the
streams radiating from the West Maui
mountains that have strong constant
minimum flow owe it to the stability
of these underground supplies whose
sources are unquestionably in a great
raany 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. It would be impossi-
BILE, by a tunnel system, to exploit
as large an area as is exposed by
erosion but this is not neces-
sary nor desirable. The geological con-
~ ha IN fra ion
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 a proper sys-
tenn of tunnels, without any unneces-
sarv and wasteful ramiicatians. Where
it is known that streams are being
partly maintained from subterranean
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
If water. but is not willing to guaran-
Zee the stability of these flows. Wnen
t comes to determining whether the
low developed will be constant, moth
ng but experience can act as a guide.
Several springs on the UIupalakua
'anch, developed upon the advice of the
writer during the last three years,
AVE all continued to give an increased
low. The flow at Polipoli has been
augmented and holds up strongly. The
Nailuku Plantation tunnel finished
.arly in 1901 and the H. c. & s. Co. tun-
leI both in lao Valley, finished a year
alter continue to hold UP their usual
low. even during the severest
thoughts.
Tunnelling at Kauaula has been con-
,tantly in progress for over two years,
md in that time there has probably
flowed out of the tunnel five billion