The two-stage soil sifting device comprises a support frame, an upper sifter, and a lower sifter. The support frame comprises a rectangular base with cross braces and four vertical uprights that support the upper sifter and the lower sifter at elevated positions. The upper sifter comprises an upper sifter frame and a first mesh having a first mesh spacing. The upper sifter is located above the lower sifter and may be pivotally inclined with respect to horizontal. The lower sifter comprises a lower sifter frame and a second mesh having a second mesh spacing. As unsifted soil placed upon the upper sifter is moved over the surface of the upper sifter some of it passed through the first mesh onto the lower sifter and then through the second mesh onto the ground, leaving debris on the first mesh and on the second mesh.

The two-stage soil sifting device comprises a support frame, an upper sifter, and a lower sifter. The support frame comprises a rectangular base with cross braces and four vertical uprights that support the upper sifter and the lower sifter at elevated positions. The upper sifter comprises an upper sifter frame and a first mesh having a first mesh spacing. The upper sifter is located above the lower sifter and may be pivotally inclined with respect to horizontal. The lower sifter comprises a lower sifter frame and a second mesh having a second mesh spacing. As unsifted soil placed upon the upper sifter is moved over the surface of the upper sifter some of it passed through the first mesh onto the lower sifter and then through the second mesh onto the ground, leaving debris on the first mesh and on the second mesh.

A vibratory separator includes a screen frame having an upper screen surface and a plurality of openings and a first screen insert disposed in a first opening of the plurality of openings of the screen frame, the screen insert having a screen surface positioned at a first height above the supper screen surface. The vibratory separator also includes a second screen insert disposed in a second opening of the plurality of openings of the second screen frame, wherein a screen surface of the second screen insert is positioned at a second height. The second height may be different from the first height. A method of processing fluid includes providing a flow of fluid to a vibratory separator, and flowing the fluid over a screen having a first screen insert positioned at a first height.

A vibratory separator includes a screen frame having an upper screen surface and a plurality of openings and a first screen insert disposed in a first opening of the plurality of openings of the screen frame, the screen insert having a screen surface positioned at a first height above the supper screen surface. The vibratory separator also includes a second screen insert disposed in a second opening of the plurality of openings of the second screen frame, wherein a screen surface of the second screen insert is positioned at a second height. The second height may be different from the first height. A method of processing fluid includes providing a flow of fluid to a vibratory separator, and flowing the fluid over a screen having a first screen insert positioned at a first height.

The invention is a portable prospecting and classifying self-contained apparatus having a bucket, a supporting classifier screen and a supported classifier screen setting freely within the bucket, having a bucket handle and a bucket lid closing securely over the bucket. The supported classifier screen has a screen mesh and a screen handle, allowing the user to lift the supported classifier screen from the bucket. The supporting classifier screen has a screen mesh which may be of a finer mesh than the supported screen mesh and a supporting classifier frame. A prospector uses the portable prospecting and classifying self-contained apparatus invention by scooping or pouring mineral material into the bucket with an earth digging scoop or gold pan. The supported classifier screen and the supporting classifier screen are adapted to classify and separate mineral material from coarse to finer grain material when poured into the bucket.

An assembly and method for gravitationally separating gold from particles, and specifically for separating small components of gold, less than 1 millimeter from small particles. A series of sieves having graduated mesh sizes, and arranged in a sequential, stacked configuration sieves the aggregate of large particles and larger components of gold. The remaining small particles and smaller components of gold fall into a container. A pressurized column of fluid is forced into the container. The fluid has sufficient flow velocity to suspend the lighter small particles, but insufficient flow velocity to support the denser, high specific gravity gold. Gold has a large specific gravity relative to the fluid and particles. Gravity causes the gold to falls into a transparent collection conduit. Manipulation of valves enables gold to redirect to a collection bin. Fluid flow is shut, enabling small particles to be flushed out through gravitational forces and excess fluid momentum.

An assembly and method for gravitationally separating gold from particles, and specifically for separating small components of gold, less than 1 millimeter from small particles. A series of sieves having graduated mesh sizes, and arranged in a sequential, stacked configuration sieves the aggregate of large particles and larger components of gold. The remaining small particles and smaller components of gold fall into a container. A pressurized column of fluid is forced into the container. The fluid has sufficient flow velocity to suspend the lighter small particles, but insufficient flow velocity to support the denser, high specific gravity gold. Gold has a large specific gravity relative to the fluid and particles. Gravity causes the gold to falls into a transparent collection conduit. Manipulation of valves enables gold to redirect to a collection bin. Fluid flow is shut, enabling small particles to be flushed out through gravitational forces and excess fluid momentum.

A sluice including an upper channel that includes a material deck and a tilted classification screen. Below the classification screen is a lower cavity located between two longitudinally aligned plenums located under the upper channel. Each plenum includes a front opening and a rear opening and an interior sidewall. Extending between the plenums is a floor plate. Fluidization holes are formed on each interior sidewall. During use, the sluice is positioned in a stream so water flows simultaneously over the upper channel and the through the front openings of the plenums. Water flowing over the upper channel separates mined material placed on the material deck so that small particles fall through the classification screen. The water entering the front openings of the two plenums flows through the plenums and partially exits through the fluidization holes and sprays over the small particles deposited in the lower cavity further separating the fine gold particles from the small particles.

A sluice including an upper channel that includes a material deck and a tilted classification screen. Below the classification screen is a lower cavity located between two longitudinally aligned plenums located under the upper channel. Each plenum includes a front opening and a rear opening and an interior sidewall. Extending between the plenums is a floor plate. Fluidization holes are formed on each interior sidewall. During use, the sluice is positioned in a stream so water flows simultaneously over the upper channel and the through the front openings of the plenums. Water flowing over the upper channel separates mined material placed on the material deck so that small particles fall through the classification screen. The water entering the front openings of the two plenums flows through the plenums and partially exits through the fluidization holes and sprays over the small particles deposited in the lower cavity further separating the fine gold particles from the small particles.

A static classifier including a vessel having an inlet and an outlet and having a vessel interior area. A classifier chamber is positioned in the vessel interior area. The classifier chamber has a plurality of openings extending through a side wall of the classifier chamber and into a classifier interior area of the classifier chamber. The plurality of openings are configured for passing particles entrained in a gas from the vessel interior area into the classifier interior area. One or more flow restrictors are arranged with the classifier chamber. The flow restrictors are configured to establish an optimal flow velocity and direction of the particles entrained in the gas, through the static classifier.