Excavating – Beneath a body of water – Adapted to excavate specific discrete material
Reexamination Certificate
1996-07-08
2001-04-17
Batson, Victor (Department: 3671)
Excavating
Beneath a body of water
Adapted to excavate specific discrete material
C209S486000, C209S477000, C209S474000
Reexamination Certificate
active
06216367
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to gold concentrators, including dredgers and high-bankers used in placer mining, and more particularly to a staged sluice for increment size classification and ore extraction.
2. Prior Art
The prior art in placer mining techniques discloses a large number of various devices sometimes termed collectors, separators, or extractors but all directed to extracting small amounts of gold from large volumes of mineral matter. It is known that the majority of gold in placer deposits is fine and very fine grain ore, the larger part of which is typically uncaptured in prior extraction techniques. Though all of the techniques seek to exploit the high specific gravity of gold, the difficulty of removing ore from the matrix in which it is found rests in overcoming detrimental effects of physical forces acting on such fine particles, such as suspension action in a slurry of the matrix in water and surface tension. These effects are exacerbated when fine ore competes with action of larger mineral aggregates, and separation and settling of ore due to its higher specific gravity is defeated. Therefore, the preliminary task before separation by specific gravity is first classification of the matrix and ore by size until ore and gangue can compete in terms of relative specific gravity with minimal effects, or at least non-dominating effects of other physical forces.
SUMMARY OF THE INVENTION
Ore with much higher density tends to settle out of suspension if allowed to compete with particles of similar size. Therefore, the present invention overcomes these difficulties in placer mining of very fine, or flour, gold generally by repeatedly classifying the gangue and ore mix by size until even the small minerals compete equally in size, thus allowing fine gold to settle out of suspension by its specific gravity higher than surrounding gangue into a scheme of traps that hold the ore for later removal. Repeated processing of the mix further classifies by size at an decreasingly smaller scale. Within each stage, ore and gangue in suspension are stratified by size within suspension with larger particles flowing above smaller particles. The larger particles are flushed away and out of the dredger with water flow while fine ore remains in suspension in lower stratification levels. The stratification is destroyed between stages along the dredger and restratified to enable separation and settling of ever finer ore with comparatively larger gangue being carried away in faster flowing upper levels of stratification, thus further concentrating the ore out of the gangue at each stage.
The primary object of the invention is therefore to provide a device to classify mineral matter by size preliminary to extracting fine gold ore from a slurry.
Another object is to provide incremental classifying in the device, at each incremental stage separating larger mineral matter from smaller mineral matter while allowing smaller matter to stratify and settle to collecting traps.
Another object is to provide a device that inverts stratified mineral matter between stages thereby destroying previously stratified matter, which matter has been previously classified by size in each stage, so that stratification of remaining mineral matter not settled out of suspension during a previous stage begins anew at each stage.
Another object is to provide a matrix of ore-capturing cones into which heavy mineral matter settles as lighter matter is carried away.
Another object is to provide a means to lift settled matter back into a less turbulent suspension in a second water flow below the cone matrix to further concentrate the ore and allow lighter matter to be carried away in suspension.
The approach to extract previously lost fine gold is to treat all size and weight material by incrementing. Optimum separation of smaller and heavier material in general has been compromised in approaches previous to the present concentrator by larger gangue that opposes selective settling by specific gravity and tends to keep fine material in suspension. It is imperative therefore in successfully capturing even fine grain ore to separate materials by size to allow similar size materials to be classified by weight. Thus, a series of size classification stages is employed within each stage, while weight classification is effected.
These objects are achieved in a sluice comprising a series of sequential, interconnected chutes. Between chutes is an inverter which inverts a stratified slurry such that an upper stratified slurry layer and lower stratified slurry layer in a given chute generally reverse position as the slurry is directed into a following chute, the slurry also reversing direction between the sections from downhill in the feed chute to uphill as it exits the inverter into the receiving chute entry end. In doing so, materials classified somewhat by size but still carried in the water, being stratified by size but not settled out of suspension, are inverted in the inverter, material of larger size being predominantly discharged first to a subsequent chute over a mesh screen and eventually out of the sluice faster than smaller material. Consequently, lighter materials carried characteristically lower in the slurry are turbulently deposited later and over larger materials with the larger materials carried away from off the screen, destroying the stratification of the remaining smaller mineral matter. Thus, each stage reclassify by size starting with remaining smaller mineral matter while larger materials move more quickly and out of the concentrator sluice.
With each incremental stage designed to treat smaller matter, the mesh of each chute screen is smaller than meshes of preceding chutes. Thus, each stage treats a material of smaller size defined by the screen mesh size eliminating size competition that tends to carry smaller heavier material in suspension with larger materials.
An array of cones is disposed on each chute bottom over which the slurry passes, adapted such that heavy matter settling from the mineral matrix is drawn into a cone of the array where it is trapped. Each cone in the array has an opening oriented downwater and includes a ridge over-hanging its opening also oriented downwater. As the slurry flows rapidly over the ridges, a low pressure region develops below in the cone cavity. The majority of the water flows over the ridges from one cone to a successive cone carrying light and large material from chute to chute through and out of the dredger. A small portion of the water flowing close to the ridges is drawn into the respective low-pressure cavities. In doing so, small, heavy material—“fines”—falling under gravity out of the slurry mainstream are biased by the small portion of water into a low pressure cone cavity.
Below the cone array is a perforated mat, commonly known as miner's moss. Because heavy gold ore tends to fall immediately when the mineral matrix is deposited on the mesh screen, it is generally sufficient to locate the miner's moss at least on the chute upper portion under the mesh screen. Also below the array, beginning at the minor's moss mat and extending downwater, is a textured mat, typically with upstanding ribs transverse to the chute water flow that also tends to capture settling material.
Because ore and unwanted material inevitably settles in the perforated mat, or miner's moss, the material needs to be lifted from the moss to reenter the classification process. If left on the minor's moss, the settled material quickly covers or clogs it, leaving it ineffective, and the concentration process at that phase is defeated. Therefore, below the miner's moss is provided a plurality of fluid nozzles, typically air holes in a network of tubes connected to an outside air compressor. With air jetted from the holes upward into the minor's moss, settled mineral matter is lifted upward with ore of high specific gravity falling back and past the air nozzles and with lighter gangue once again returne
Batson Victor
Tingey David L.
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