Dredge HP Horse Power Requirements
In calculating the horse-power consumed by suction and by bucket dredges, figures have been taken from the various official reports on the mining industry in New Zealand, dates and pages in each instance being given. The calculations are made in theoretical horsepower, and for easy references are given in tabular form. The difference in the […]
Suction Dredge
These machines consist essentially of a floating structure, supplied with a powerful pump of centrifugal type, raising sand and water through a suction pipe. Characteristic types of suction dredges are the Ball and the Welman. The Welman patent pump is in many respects similar to a centrifugal pump; the runner, however, is differently constructed, the […]
Bucket Dredge
The bucket dredge may be described as a continuous dipper dredge, the material being raised by a revolving chain of dippers or buckets, which scoop or dig into the deposit. The principle and system of raising material in these machines are almost identical with those of harbour dredges. The favourite type of bucket dredge is […]
Types of Dredges
The type of a Dredge is defined according to the Nature of the Work they do. Under this heading bucket dredges may be classed as: River dredges; paddock dredges. The river dredge is designed to work with some depth of water underneath it, and is not called upon to cut its own flotation. It is, therefore, not […]
Electric Dredge
Small electric dredges are great where water power is available within reasonable distance, electricity may be generated and transmitted by cable to the dredge, proving an economical substitute for steam, especially in localities where fuel is dear. The small space, too, occupied by the plant, and the ease with which it is handled, make electricity […]
Steam Dredge
The first steam dredge of the bucket type was launched on the Clutha in 1881. Such dredges differ from current-wheelers only in being provided with engine and boiler in place of the undershot wheel. The use of steam machinery, of course, increases the initial cost, adds to the working and maintenance expenses, and necessitates the […]
Current Wheel Dredge
In the Current-wheel Dredge, the mechanism on these dredges is driven by an under-shot water-wheel, placed at one or at both sides of the scow and rotated by the current. Such dredges work with most safety and regularity in about a 3-knot current. An instance of a machine of this kind is the Mannherikia dredge, […]
Gold Dredge Components
Dredge Hull Among dredging hands, the “ hull ”—namely, “ port ” and “ starboard ” pontoons tied together—is usually termed the “ pontoon ” or “ pontoons.” The ordinary hull consists of two long, narrow pontoons, joined together for about a third of their length by a third small one, equal in width to […]
Dipper Dredge
In its primitive form, the dipper dredge consists of a barge or pontoon, to the side of which is attached a long pole carrying a strong canvas or hide bag, or iron bucket, which is termed a ladle, spoon, scoop, or dipper, and which at times is provided with a blade or shovel. To the […]
Air Jig – Paddock’s Pneumatic Separator
The Paddock pneumatic ore separator is a jig, in which air is used instead of the fluid more commonly employed—water. Like the water jig, it consists of an inclined sieve, over which the crushed ore is passed, and through which the air is blown into the ore. The air current is intermittent, and being proportioned […]