The Bond ball mill grindability test is one of the most common metrics used in the mining industry for ore hardness measurements. The test is an important part of the Bond work index methodology for designing and measuring the efficiency of mineral grinding circuits.

There are many different techniques to process the vast variety of ores that came out of western mines, and many mines often employed their own milling methods. This article will focus on the most common type of ore processing facility – the stamp mill.

 — Calculate a Mill's Operating Work Index. Use this online formula to calculate a Ball Mill, Rod Mill or SAG Mill Operating Work Index. Based on Fred Bond's work you can estimate the energy used into your grinding circuit.

The SAG mill works by rotating the drum at a low speed, which causes the steel balls inside to cascade, fall and impact with each other. This impact crushes the copper ore against the steel balls until it is small enough to pass through perforations on the side of the drum.

The smelter would then process the ore further into pure metal. This process of separating the waste rock from the metal prior to smelting is called milling. Although not all mills were the same, the following is an outline of a basic mill process.

Miners rely on semi-autogenous grinding (SAG) mills and ball mills to liberate metals from ore. They are familiar pieces of machinery that are seen continuously turning at processing plants. Availability with this machinery is key.

Steel is primarily produced using one of two methods: Blast Furnace or Electric Arc Furnace. The blast furnace is the first step in producing steel from iron oxides. The first blast furnaces appeared in the 14th century and produced one ton per day.

 — The basic grinding action in the Tower Mill is abrasion. The absence of impact limits practical feed size to 5mm. Because there is greater pressure between media and less production of heat and sound, the device consumes less energy than a tumbling mill to perform the same work.

Ball mills consist of the following components: Inlet – crushed ore is fed to the ball mill through the inlet. A scoop ensures the feed to the mill is constant. Discharge – reduced feed exits the mill through the discharge. Ball Mill Components. Drum – the drum is the cylindrical casing of the ball mill.

 — AG/SAG mills grind ore through impact breakage, attrition breakage, and abrasion of the ore serving as media. Autogenous circuits require an ore of suitable competency (or fractions within the ore of suitable competency) to serve as media.