C.—3

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Subject K. — A Knowledge of Under ground Surveying and of making Plans of Underground Workings, showing the Dip or Inclination and Strike of Reefs or Lodes.

1. (a.) The accompanying diagram represents a mining claim, the positions of a shaft (2), and points (3 and 4) in the underground workings. You are required to compute the distance which should be driven from 4 to 5 to strike the eastern boundary of the claim; and please also compute and give the distance 5 to 6. (b.) There is a fall from the bottom of the shaft (2) to station (3) which was observed to be 10° 15. W r hat is the difference in height, in links? (Maximum number of marks for question (a) 45, (6) 10.) 2. («.) How would you transfer true bearing to the underground traverses? and (&) what precautions would you adopt to avoid errors in the underground survey of an extension mine .and encroachment on adjoining claims? (Maximum number of marks for question, 20.) 3. Describe shortly the terms "dip" and "strike," and give illustrations. (Maximum number of marks for question, 25.) Note.—After the foregoing examination the candidate will be required to undergo an oral examination by the Examiner, including questions (1) as to the use and adjustment of the theodolite, prismatic compass, clinometer, and other instruments; (2) as to measuring accurately horizontal and slope distances with steel tapes and long bands; and (3) as to the best manner of keeping field notes so as to indicate clearly all bearings, measurements, and other details relating t© underground workings. Subject A. — The Different Modes of reducing and pulverising Ores. 1. State where and by whom you were employed, and. the dates you were engaged in crushingbatteries where bullion was recovered by cyanide-of-potassium treatment. 2. Describe the actions of Blake-Marsden, Gates, and Dodge ore-breakers; give the speed at which they are driven; and show by sketch where th,ey are placed in relation to stamps in a crushing-battery. Also state what you consider the most economical dimensions to which the ore should be broken before it goes to the stamps. Give your reasons fully. 3. If you were constructing a crushing-battery of thirty heads of stamps, with ore-breakers and concentrators, show by sketch-plan how you would erect it, giving the levels of the different portions of the battery with accessories in relation to the lowest floor-level. 4. A Pelton water-wheel 6 feet in diameter is used to drive thirty heads of stamps. Each stamp is 1,200 ib. weight, having a drop of 6 in. and making 102 drops per minute. The wheel is under a 200-feet head of water. Show by calculation the number of revolutions at which the wheel requires to be driven to give its maximum power; also the diameter of the nozzle to give the necessary quantity of water to supply the requisite power to do the work, allowing the Pelton wheel to give 80 per cent, of the theoretical power of the water and that friction in working the battery absorbs 33 per cent, of the power transmitted by the Pelton wheel. 5. Describe the action of a Krupp mill. Give the speed it is driven at, the-horse-power required to work it, and its crushing-capacity through a 40-mesh screen in twenty-four hours. 6. If you were ordering a steam-engine to drive a stamp-battery where the theoretical power required was 80-horse, show by calculation the diameter of a single cylinder capable of developing that power: the initial pressure of steam being 100 Ib. per square inch, cut off at one-half the stroke; the piston-speed being 450 feet per minute. 7. What is meant by " concentration " of ore? Why is it required? And state the class of ore most suitable for concentration. Also describe fully how the concentrates are treated to recover the bullion they contain.