Apex:
The point of a cone. The point of a cyclone from which coarse material is discharged. In a cyclone, it is open and the size of the opening affects cyclone performance.

Argentite:
A silver sulphide mineral (Ag2S). The most important silver mineral in the ore.

Barren Solution:
The cyanide/lime process solutions that have had the gold and silver removed.

Clarifier:
A filter designed to remove small amounts of fine solids to make a crystal clear solution or water.

Classification:
A method of separating different size particles that relies on the relative movement in a fluid, as a function of their weight and surface area. A cyclone is a classifying device.

Controller Cyclone:
A device for separating large from small particles. It consists of a conical vessel with a cylindrical top section into which a slurry is fed tangentially. The swirling motion of the slurry in the cyclone subjects the particles in the slurry to high centrifugal forces which causes the larger particles to be move to the wall of the cone from where they are removed via the apex as a dense slurry. The finer particles and most of the solution remains closer to the centre of the cone from where they are removed via the vortex finder.

Cyclone Overflow:
The fine product that comes out of the vortex finder.

Cyclone Underflow:
The coarse product that comes out of the cyclone apex.

Differential Pressure Switch:
A pressure switch that monitors pressure at two locations, tripping if the two pressures are not the same.

Drum Filter:
A filter consisting of a cylinder or drum mounted horizontally. The circumference is divided into sections and covered with a filter cloth. The drum rotates slowly about the axis. The lower part of the drum is submerged in pulp and subjected to vacuum. The solids accumulate on the surface of the drum as a cake. Vacuum is maintained for most of the rest of the cycle to reduce cake moisture. The section to be discharged is blown as it gets to the appropriate position.

Dore:
A blend of gold and silver metal.

Filter Cake:
The solids that accumulate on the filter cloth as moisture is removed through the cloth.

Filtrate:
The liquid that passes through the filter cloth. With the drum filters and clarifiers, the filtrate is pregnant solution and with the precipitate filters the filtrate is barren solution.

Flocculant:
A chemical which causes fine particles to stick together in clusters (flocs). These larger agglomerations behave in a number of processes as large single particles (but of lower density than the original solids) which can be helpful in both thickening and filtration.

Flux:
A mixture of substances that react with undesirable impurities to produce slag during smelting.

gpl:
Grammes per litre.

Jog Button:
A pushbutton which can operate a motor only when it is pushed and held. The circuit does not seal- in.

Latch/Leach:
A process where a liquid or solution reacts with a solid and causes it to dissolve.

Lime:
Calcium oxide or hydroxide. An alkali made by heating limestone.

Mesh:
A system of size measurement used for screens. The mesh number is the number of screen openings per inch on a standard square opening woven screen.

Micron:
One thousandth of a millimeter or one millionth of a meter. Used for measuring very small distances such as openings in screens in the metric system (SI units).

MCC (Motor Control Centre):
The MCC is a rack containing motor starters for the various low voltage motors in the plant.

Ore:
Rock which contains mineral values that can be recovered at a profit.

pH:
Expresses both acidity and alkalinity on a scale whose values range from 0 to 14 with 7 representing neutrality. Values less than 7 increasing acidity, and values greater than 7 increasing alkalinity.

P&ID:
Piping and Instrument Diagram.

PLC:
Programmable Logic Controller.

PPM:
Parts per million. A way of expressing analytical results for small concentrations.

Precipitation:
The removal of dissolved substances from a solution by the addition of a reagent to produce a solid and a barren solution.

Pregnant Solution:
This is the cyanide and lime process solutions that contain dissolved silver which is to be recovered in the recovery circuit.

Pulp:
Another name for slurry.

Pulp Density:
The ratio of solids and liquid in a pulp. It can be expressed as either.

• Wt. of solids = % solid by
  Wt. of pulp weight
• Wt. of 1 litre pulp = S.G.
  Wt. of 1 litre water

S.G. = Specific Gravity

Reclaim Water:
Solution reclaimed from the tailings pond for use in the process.

Repulp:
Mix solids, that have previously had liquid removed, with liquid to procduce a pulp. For example, add water to filter cake and mix together.

R.O.M. Ore:
Run-of-mine ore; This is ore as delivered to the mill from the mine. It is the real feed to the process plant rather than an ideal or theoretically achievable feed.

Sampler:
A unit that takes a small portion of the process stream as representative of the full steam. To get a suitable size sample several successive stages of sampling may be necessary. Each stage is named thus:

• Primary
• Secondary

Seal Water:
Water that is pumped into the small space between a rotating shaft and a fixed case to prevent leakage of abrasive material from within the equipment damaging the shaft or casing.

Slag:
The ‘glass-like’ lower density waste material produced in smelting of metals.

Slurry:
A mixture of solids and liquid such as ore particles in process solutions or water.

Smelt:
Melt a mixture of substances so that chemical reactions take place that purify one of the phases by removing impurities in a slag.

Specific Gravity:
Denotes the ratio of the density of a substance to the density of an equal volume of water.

Square Root Extractor:
Pressure, as measured by an orifice plate, gives the square of a flow in a pipe. If just the flow (not its square) is needed, the square root extractor receives the squared flow signal and outputs a linear flow signal.

Tailing:
The waste material discharged from mineral processing plants, usually a slurry.

Thickener:
A piece of equipment for separating liquid and solids. It consists of a tank into which pulp is fed and the solids allowed to settle. The essentially clear liquid overflows into a collecting launder around the tank rim. There is a slowly rotating mechanism mounted in the centre which scrapes the settled solids towards the centre.

Vortex Finder:
A pipe inserted into the cyclone concentrically with the axis and opposite the apex.

Waste:
Material that contains no valuable minerals or insufficient valuable minerals to be mined and processed at a profit.