The Wallace miner. [volume] (Wallace, Idaho) 1907-current, 1915-12-23
PANAMA CANAL SLIDES
MUST MOVE MUCH MUCK
DISCUSSION OF CONDITIONS AT
cuLEeRA CUT BY COL.
COCKTAILS.

Colonel G. w. Goethals describes
the conditions along the Panama canal
and the difficulties with slides at Gu
Zebra cut in recent issue of the New
York Sun, from which the following
extract is taken;
After the United States forces be-
gan work, sliding at Cucaracha con-
tinued, and In 1906 a geologist was
employed who, after spending some
months making personal examination
OF the geological formation Of the
country traversed by the canal, made
a report on the subject, which was
published in full In the annual report
of the Isthmian canal commission for
1907 In this report he states:
THE relation of the Isthmian geol-
ogy to the varied problems of canal
construction is, in all cases, intimate
One of the problems that Is closely
connected with the geology Is that of
the excavation of the cut in the CEN
trail area. Actual work has advanced
so far In this region, however, that
geology can add little to the practical
information acquired in the course of
the excavation that has already been
made. A less evident, but perhaps
closer, relationship exists between the
geology and the problems attendant
upon the construction of the locks and
dams, while the necessity Of obtaining
large quantities Of building material
near the points where locks and regu-
lating works are to be constructed
calls for special study"
Value of the GeoIogist
From this 1t would appear that the
excavation in the cut would be attend
ed with few difficulties other than
those which are usually encountered
in work of such character and magni-
tude. and that the services Of geolo-
gist In connection with the canal
would be of value with respect to the
locks and the construction materials
required therefor, rather than the ex-
ctNdllol liIouBil tHS cunllHtItdl III
vide. However he discusses subse-
quently, in the same report, the con-
ditions of the cut in the vicinity of
our present difficulties, in a manner
still more explicit, as follows:
THE physical character of the Gu
Zebra beds, consisting as they do of
alternating layers of sandstone and
shale Is peculiarly favorable to land
slides. Structurally, however, the
strata are so nearly horizontal, or have
such low southerly dips north of Gold
Hill, that movements involving large
masses Of rock are improbable, while
slopes of suitable angles will do away
with the danger of minor slips.
Gold Hill Is bounded on the north
and south by faults, the mass Of the
hill having sunk with respect to the
rocks on the other side of the faults.
During the process of faulting the
strata We're twisted to the eastward, |
and now have steep dips in that di-
rection. This structure is also COM
plicated by large masses OF intrusive |
basalt which were included in the Gu
Zebra beds prior to the faulting The |
induration resulting from these intru-
slons has been so extensive that all |
the rocks in Gold Hill are now very
hard and firm, and with the sediment
airy beds dipping into the hill the con-
ditions are such that landslides are
most unlikely to occur
Soft Beds in culebra.
In Contractors Hill heavy brec-
ella member of the Culebra beds dips
in the direction of the cut. 1t Is be-
Iieved that the soft Culebra beds will
be encountered below the breccias. II
these beds are found to have strong
northeasterly dips-that is, IL they are
Inclined in the direction of the cut, as
The surface indications suggest--it
will be necessary to make compare
lively low slopes on the southwest I
side of the canal at Contractors Hill !
N order to avoid any possibility of /
andslides. This is the only point {
along the canal where such move {
nents are at all possible. In my opin- {
on, the danger is not serious, but or \
iinary prudence requires that If the {
soft Culebra beds are found beneath
he breccias to dip at angles of more {
han Is degrees in the direction of the q
ut the angle of the slope be so re- {
luced as to do away with all danger
4 slipping. {
Between Gold Hill and Cucaracha,
IN the northeast side of the cut, land A
lides have taken place frequently in 1
he rainy season. The materials in I
olved in these slides are purely sup 4
rficial; in some cases French spoil A
anks have slipped The cause In all
asses seems to be the saturation of n
he unconsolidated surface material II
nd its movement on layers Of slippery T
lays either In the Culebra beds or q
esidual clays upon which spoil was O.
umped G
1.-THE basin south and east of Gold r
fill collects large quantities Of water
uring the rainy season, and this es- N
apes through no well defined drain In
ge. but in springs along the edge of m
he cut. In some cases surface soils II
r even the rock of the Culebra form q