Tonopah bonanza. [volume] (Butler City [i.e. Butler], Nev.) 1901-1909, 1904-07-16
TONOPAH BONANZA
CARE OF WIRE ROPES.
What Should be Done to Pre-
serve Them.

A percentage OF buyers OF wire
winding rope or cables leaves the de-
termination OF the size, strength and
breaking strains Of the cable to the
supplying firm, to which they furnish
such details as depth Of shaft, weight
to be hoisted and whether the shaft
is vertical or incline. If the suppller
is unfettered by consideration OF
price and has a reputation this Is a
GOOD plan, as rope constructed by
reliable makers has factor of safety
five times greater than the STRAIN
which it may undergo and which
varies according to special conditions,
such as winding speed, size OF drum
and sheaves, etc, Wire ropes are
made of strands twisted together
around a hemp core. The strands
NAV be of Swedish iron, crucible steel
or plough steel. Plough steel, under
special conditions, is to be recon-
mended, but it is less pliable and more
brittle than crucible steel, the gen
eral experience going to show that
ropes made of best crucible steel
wires last longest proportional to the
work done.
AS an exampe Of life of rope may
be- quoted the record of ASSOC feet
deep shaft at the mines of Przibram
in Bohemia. The rope was made OF
crucible steel and was proportional
to have permanently, a breaking
strength OF seven times the load,
based on the aggregate Of the wires
without any percentage reduction
for twist or unequal strain. The rope
made 100, 900 trips a year, was wound
On the drum in two layers, and lasted
more than three years. 1t may be
stated that a rope in an incline shaft
will wear out more quickly than in {
vertical shaft. In i%uclines the lower
end of the rope receives the principa
wear, because in descending it has t
start the carrying rollers into motio
by friction, during which period it eX
periences considerable wear by sic
ING over the rollers. The lower en-
should therefore be carefully an
frequently inspected.
Where the water in the mine
acid, corrosion will naturally ac
more quickly on ropes 10 incline'
since they are more liable to pic
up moisture from the ground an
drippings from the roof. Actu;
wear is about proportional to IL
number of trips made by the rope i
dependent of the time Of servic
while corrosion is probably propo
tional to the time OF service, ind
pendent Of the work done. In vertic
shafts cables winding in a single lay
on a grooved drum wear much lie
than those wound on in several la
ers, as in the latter ease there
asways ahock when it arrives at t
drum fauge and has 70 mount su
denly on top of the layer Just col
pleted. Inspection as to wear a
corrosion should be frequently mac
A rope must be kept well Tub
Gated, as this will help to prolong
life, and it should be discarded
soon as il shows appreciate cor
sion. II a single wire breaks i
rope It's total strength is only Sigh
reduced, particularly il ii is compo!
of a large number of wires. II m
wires are broken, then, unless
breaks are neal the same poin.
the rope the strength will be
duced only in proportion to that 0
single wire because of the spite
effect for the distance which ger
ally exists between breaks. But
breaking Of wires would seem to
dictate brittleness of the rope an
would be safer to condemn it.
cost of a rope in the equipment o
mine IS SO small that it is advisa
from all points Of view, to buy
best %procurable, but too much
lance must not be placed in ST
meuts claiming great duration OF
for a particular make Of rope.
conditions under which hois ting ca
operate are so varied that it is