ing
only 7 feet by 6 feet was lowered to the eighth level (488 feet), and
experimental. holes were bored in all directions, thus yielding
information as to the contents of the mine which could not otherwise
have been obtained without years of labour. The machine used in this
case bored three thousand feet in six months, the only repairs needed
at the end of that time being trifling. Well, therefore, may Mr. Bayne,
the President of the Bendigo School of Mines, say :—
"
As a prospecting tool then, the Diamond Drill is quite unique, and
accomplishes results that can be obtained by no other known process. It
should be remembered at the same time that it is a scientific
instrument and not a divining rod. It must be used with discretion, and
its indications read intelligently. It does not point by some
inscrutable agency to payable reefs, but it tells us with great
certainty and with remarkable expedition whether we shall come to
auriferous quartz if we dig down or along a certain direction within
the 2,000 feet or more. A negative answer saves the trouble and expense
of sinking or driving in that direction, and we have then only to put
further questions by varying the direction of the line of search. Their
\ise enables a larger amount of work to be performed and thereby
increases the demand for labour, and it is to be noted that in the
States where these drills find such favour, the price of labour reaches
from 10s. to 13s. a day, showing that the drill recommends itself as
much to the miner as to his employer. At the Great Northern Company,
Stawell, Victoria, where one of these underground drills is now at
work, in 60 shifts of 8 hours each, or 480 hours, between April 27th,
and July 5th, 1880, it has bored through 483 feet 3 inches, commencing
at a depth of 800 feet. This is looked upon as very satisfactory,
considering the hardness of the stone, a sample of which may be seen at
the School of Mines, Sandhurst."
An extract from the Scientific American of
28th Feb. 1880 states that " Mr. A. J. Severance, of San Francisco,
says that the Diamond Drill has played a very important part in
developing the mineral wealth of the West. The first great
treasure-house which these drills opened up was that known as the
Consolidated Virginia, and the California Bonanzas, which have yielded
Twenty-two million two hundred and ninety one thousand pounds sterling,
of which the stock-brokers have received Fifteen million four hundred
and sixteen thousand pounds sterling, in dividends. One of the owners
of the mine told Mr. Severance that the Diamond Drill had realised for
him One million pounds sterling. All the principal Comstock mines, and
many of the largest mining properties located in California and Nevada,
use these drills. They are also extensively used in Colorado, have
pushed their way to most of the Territories, have been introduced and
operated in New Mexico, Old Mexico and Australia. The Japanese
Government has also been supplied with them. Mr. Severance enjoys the
distinction of having perfected the Diamond Drill, and of proving its
utility by running a horizontal hole (then regarded an impossibility)
eight hundred feet, taking out a complete cylindrical core, and showing
the strata of every inch of rock passed through. This was done in
Vermont. Soon after he introduced the drill upon the Pacific Coast,
with the results already noted."
Figures
3 and 4 show the tunnel and mining drill and the open cut and quarry
drill respectively. The former when set up weighs about 300 lb., the
size of the bit is li in. diameter, and the price £261 ". the latter
weighs 250 lb., size of bit 1 to if in. diameter, price .£209. These
drills might be useful in Ceylon not only for gold prospecting but
perhaps for sinking wells in the drier parts of the island. This brings
us to the " patent wheel earth scoop," manufactured by Messrs. Robinson
& Sons of Melbourne, for making dams and tanks to retain rain
water. The prospectus states that " It is as simple as it is possible
to be made. It is very strong, being made nearly wholly of wrought
iron, so that there is little chance of its breaking. The draught is
onl half tha required for skid scoop of equal size, besides being
