Ore Sampling Methods: Good & Proper
From the old-fashioned “ grab-sample ” to the modern timing- device, which takes a machine-sample with mathematical precision, there is a wide gap, which was only crossed by many years of toil and unremitting endeavor. Even to-day, notwithstanding the advancement in the art, “ grab-sampling ” is still practiced—sometimes to afford the unscrupulous mine-promoter a […]
Gold Dredge Components & Parts
The design and specifications submitted in this paper are not offered as satisfying all conditions of gold dredging. Many rich stream-beds would not give “ elbow-room ” for such a dredge: many otherwise favorable gold-bearing areas are too small to warrant the cost of its installation; and, in some localities, as I have already remarked, […]
Hydraulic Gold Dredging
Repeated failures in attempts to work gold-bearing gravels by means of suction dredges have created the impression that this method is impracticable. The suction hydraulic gold dredges have failed from three special causes: excessive wear and frequent breakage of pump-shell, runners and liners; inability to dredge compact gravel which would not readily move towards the intake; […]
Tunneling Machines
If we could keep the rock-drills running all the time, and eliminate all the other operations except as they could be carried on without interfering with the drilling, that would certainly seem to promise more rapid progress. This is the idea which the inventors of the tunneling-machines are working on, and it is no wonder […]
Driving Mine Headings in Rock Tunnels
This paper deals specifically with heading-driving as distinguished from the broader term tunnel-driving. A heading is a pilot or path-finder for the main tunnel. Some headings are complete tunnels in themselves; that is, conditions at times warrant driving a heading the full diameter of the proposed tunnel. A tunnel 10 ft. in diameter might be […]
Underground Gold Mine Development – Sampling
This paper is intended, in the light of recent investigations, to call attention to some of the essential features of good practice in sampling and mine-valuation. Mine sampling may be divided broadly into two classes: development-sampling and computation of ore-reserves; and, stope-sampling and estimation of stope-values. Development Sampling It is with development-sampling only that this […]
Adjustable Thermo-Electric Pyrometer
Frequently in using a thermo-electric pyrometer for measuring the temperature of a furnace, a hole is drilled at the back or side of the furnace, through which is introduced the tube containing the thermocouple. At times the couple is left almost where it drops, for the reason that it soon becomes too hot to be […]
Small Mining Drills
The purpose of this paper is to discuss the relative merits of the large 3 1/8-in. machine and the small mining drill 2¼-in. tappet machine in driving development-headings; and although the data here presented were obtained from cross-cut headings alone, experience has shown that the results are equally true in drifting, raising and winzing. Recently […]
Cost Accounting in Mining
In the zeal for opening up new ore-bodies, or for extracting the ore from attractive bodies already opened up, we very often lose sight of the fact, that, after all, the operation of a mine is a business proposition, pure and simple, and, for the best working-results, should be treated upon a strict business basis. […]
Hydraulic Sluicing
Supposing that a claim is suitable for hydraulic sluicing, the first thing to do would be to ascertain what is the probable volume and pressure of the water supply. This can be closely approximated by means of an aneroid survey. The facilities for the disposal of the tailings should next be ascertained. As mentioned before, […]