Gadsden,
superintendent, at the time of his visit to the mine of the New Mine
Sapphire Syndicate. The earlier mining operations of the New Mine
Sapphire Syndicate consisted chiefly of open cuts, of which
probably
nearly a mile were made along the outcrop of the sapphire-bearing dike.
These cuts were from 10 to 60 feet deep, in one place the dike material
being removed to a depth of 90 feet. The ways of the cuts were held
apart by stulls as needed. At present the sapphire ore is all obtained
from underground workings. The latter consist of a shaft 100 feet deep
with drifts in each direction from the bottom. The shaft is located in
a smaller coulee or valley crossing the dike. The west drift is about
2,000 feet long and nearly 200 feet below the surface of the hill on
the west of the coulee, while the levels above and one of the stopes
reach nearly to the bottom of the 90-foot open cut in this hill. The
east drift was carried nearly 800 feet, with stopes above at varying
intervals. At one place in this drift the dike has been stoped out to
the surface. The nature of the dike as exposed in these workings is
variable in both richness and size. Nearly barren places occur in the
dike where the latter seems to be choked with limestone, between the
fragments of which there is but little dike material. The barren places
commonly occur where the dike pinches down to smaller dimensions, which
changes in size were doubtless caused by the jamming of limestone
fragments included in the magma in the narrower parts of the fissure at
the time of intrusion. In places the walls of the dike are rough where
the edges of the limestone strata were broken during the Assuring and
fragments were torn off by the intrusion of the dike. Jagged furrows or
elbows in the limestone walls show where such fragments were torn off.
In some places a single flat bedding plane of the limestone or steps,
including several beds, form the bottom of these furrows, which are
somewhat wedge-shaped toward the top.
Contrary
to reports circulated during 1906 that the work of this company was
hindered by the difficulty of disposing of the waste and slums from the
sapphire washing, a larger supply of ore was mined and treated during
1907 than ever before. Instead of containing chemicals injurious to
vegetation, as claimed by some of the ranchers along the river below
the mine, the slums have been shown actually to improve, for raising
crops, the lands on which they are turned. Analysis of the slum is also
reported to show the presence of nitrates and phosphates, which are
helpful to any crop growth. To test this, Mr. C. T. Gadsden,
superintendent of the mine, turned the water carrying the slums over
portions of the ranch land owned by the company. Oats, alfalfa, and
vegetables were successfully grown, both where the slums were turned
over crops already planted and where the vegetables were planted
directly in thick deposits of slum. In each case vegetation was most
luxuriant where the slum was thickest. The coarser sands from the
sapphire washings were removed by a sand trap from the sluice ditches,
where the grade was low, to keep the latter from clogging up. This was
accomplished automatically by a simple device operated by an undershot
water-wheel in the sluice.
In
some respects the method of separating the sapphires from their matrix
is similar to that of separating diamonds from the "blue earth" of
South Africa. Near the surface and to a depth of 20 feet and more, the
dike rock was decomposed by weathering to a yellowish
