The Wallace miner. [volume] (Wallace, Idaho) 1907-current, 1912-05-16
GREAT BLAST IN WASHINGTON QUARRY.

The great blast in quarry No. 10 Of the Hercules Sand
stone company Tenino Wa proved perfect success say
Mining and Engineering World The purpose of the blast
was to loosen 100000 tons of sandstone for in the govern
ment ey Grays Harbor The rock broken into
great blocks that lie in convenient position for further
breaking and loading
Hercules quarry No. is situated about mile north OF
enno, town the main line of the Northern Pacific rail-
81 miles south Of Tacoma One hundred thousand cubic
yards OF sandstone have already been taken from the quarry
with the aid of channeers The remaining rock mass stood
the form of jung point about 500 feet wde 5O
to 70 feet in height at the face measuring from the quarry
floor and cut off at each side by gulches From the top Of
the quarry face the rock soped gently upward until at dis
ance OF 200 feet back from the face had average height
of about Is feet above the quarry floor The rock medium
grained greensh sandstone Of massive structure The quarry
floor consists of bed Of slate which has been penetrated by
diamond drill to depth of 11S feet Between the slate floor
and the everything sandstone layer of clay nearly inch
thick
The chambers for the blasting powder consisted
tunnels with atera these tunnels not driven exactly
at right angles to the face but parallel series OF vertical
joint plans making angle of about 70 degrees with the face
The southern tunnel $50 feet long, with three piers of lat
erals from 30 to 50 feet each length located opposite
other Two hundred feet distant another parallel tunnel
1856 feet long with four pairs Of aeras each so feet long
the side toward the southern tunnel and from 20 to so feet long
on the side towards the open edge of the hill.
The tunnels measured about by IL feet in
ton and were driven partly with the aid of machine drills One
thousand hundred and wentyfour kegs 43 100 bs
of black powder and 1900 pounds Of 60 cent dynamite
tamped with pas from the quarry except that for distances
Of to feet from the main tunnels the tampng consisted of
ties set solid cribs and wedged the main tunnels also
tamped The combined system Of tampng proved very eff
ecve The fact that each tunnel driven the bed Of
The slate undoubtedly aided in producing distribution
Of the force of the blast
Two sets Of electric decorators used throughout
the top of each chamber and in the BOTTOM the upper
being circuit which connected in series to the circuit
the lower set The wires led battery located 1900 feet
front Of the quarry open ground Promptly at 23O
Major B. Cavanaug in charge of the engineering work
he Grays Harbor ey sent current through the big charge
10 the hundreds of spectators the point Of the hill appeared to
vde into great blocks which the air distance of Is
20 feet In instant dense of black smoke hid the
Whole quarry Numerous spas thrown hundreds of
ee in the air and few large blocks did minor damage
the quarry buildings but in general the effect of the powder
exactly according to the design of the of the quar-
The face of the former quarry tumbed forward on the
quarry floor to distance of 60 to 80 feet The greater por
ion of the rock from the big blast lies in blocks weighing
TONS while few of the weigh several thousand
ons each.
peculiar feature of the blast which although unexpected
oved to be of great benefit the existence of vertical
on plane extending almost completely the point the
ill just back of the ends Of the tunnels On the plan of the
last dotted line had been drawn show the probable limit
distance to which the effect of the blast would extend back
nto the hill