Effect of Air Flowrate on Flotation Column

On a flotation column cell, the variation of concentrate flowrate, clean coal yield and product grade with air flow rate are shown in Figure 4. These tests were carried out using a 5 wt. % feed slurry. The results show that the concentrate flow rate, yield and product ash content increased with air flow rate. … Read more

Visman’ General Sampling Theory

A comprehensive analysis of the entire range of related studies would require a lengthy discussion. Instead, this paper will focus only on the work of Visman (1962, 1969), because his work is part of the current ASTM D2234 standard on coal sampling (American Society for Testing and Materials, 1985). Visman’s work attempts to empirically determine … Read more

How to Reduce Ball Mill Overload Risk

Two different circumstances must be addressed for the reduction or elimination of overload risk: a) in existing operations, or b) in the design of new grinding circuits. The methods necessary are in the first case an adjustment of operating conditions; and in the second an adjustment of mill shapes. Existing Operations: from Equation (1) for … Read more

Column Flotation BIAS

Counter Current flow of mineralized bubbles & wash water The column underflow is always of slightly higher volume than the feed. This volume imbalance, called BIAS in the control system, is made up by wash water inserted at the top of the column. Part of this wash water travels down the column to exit with the … Read more

Gold Refining Contract

The operator’s relationship with the refinery depends entirely upon a well-defined written contract, good representation at the refinery and the use of reliable assay laboratories. While all contracts are similar in that they are meant to safeguard the interest of both refiner and miner, it is not unusual to find a single refinery writing a … Read more

Gallium Uses

Gallium: Cominco has been at the interface between the semiconductor materials and the components industries since the commercialization of the transistor in the early fifties. Based on our commitment to R&D, we have become the largest merchant supplier of several specialty semiconductor substrates including LEC-grown semi-insulating gallium arsenide wafers on this continent. The following remarks are … Read more

Ball Mill Circuit Classification System Efficiency

Fines may be defined as any material smaller than a specified product size, and “coarse” as any material that is larger. The target 80 percent passing size of the grinding circuit product is a convenient reference point, as it is often used to express the grind size objective. This size is close to the modal … Read more

Underground Mining Geology

In the previous topic we learned that the economics of mining is particularly related to the amount of ore that can be produced and the amount of waste rock that must be moved. That makes underground mining particularly suited to structurally compact ore bodies with high grade ores which don’t require an extensive network of … Read more

Underground Mining Methods

The choice of an underground mining method depends on a range of factors and these include; the size and shape of the deposit, the orientation or slope of the deposit, the depth of the deposit, geological structures, characteristics of the ore and the surrounding rocks and issues with gas and water. In combination, these factors … Read more

Open Pit Mining

In model 1 with Stephen, and in the previous topic, we saw that the geological aspect is one of the main factors that affect the design of a surface mine. What are the characteristics and other aspects should be taken into a code for the final configuration of the surface mine. Between them, we have … Read more