Use of Simulation Models to Design, Optimization and Control of Wet Grinding Circuits
Mineral comminution is an important and expensive industrial process and modern comminution circuits are complex. There is considerable economic incentive to optimise circuit design and performance and to operate circuits at maximum efficiency, and these aims may be achieved by setting up mathematical models of the volts in a circuit on a digital computer and […]
Particle Size Distribution of Grinding Mill Products
This report briefly reviews the essential features of moment analysis and describes extension of this method to size reduction by ball mill grinding. Method of Analysis of Size Distribution Data Size analyses of mineral products are usually made by screening with a set of sieves having mean apertures arranged in the Tyler scale, which is […]
Optimizing Grinding and Regrinding Capacity in Mill Design
The intent of this paper is to try to answer the complex question: “How much grinding capacity should be designed into a new mining – milling project?” Much work has been devoted to the technical aspects of grinding, the “how” of grinding. But, in the writers’ opinion, the economically important subject of optimizing grinding capacity in […]
Electric Drives for Large Ore Grinding Mills
Ore grinding mills are really just slowly rotating barrels, but barrels that are growing in size so fast that the application of electric drives for them is rapidly approaching a technology like that for wind tunnels or pumped storage drives. This application is particularly worthy of care because some 40% of the 75 megawatts of […]
Coarse Grinding in a Ball Mill
Rod mills were developed as a logical substitute for the rolls crusher when larger tonnages had to be handled, on a continuous basis. Today, with even larger tonnages to process, the trend is to install larger equipment, automate the plant and develop the highest availability possible, in order to cut costs. The rod mills, because […]
Basic Control Strategy for Mineral Processing
The principle purpose of applying control to any process is to improve its profitability. Even when considering the impact of a plant on its surrounding ecology this is still true, since the sanctions felt most immediately from violations of the regulations are the economic penalties or fines which result. Economic performance can be improved within […]
Semi-Autogenous Liners
The never ending search for lower unit costs led Pima Mining Company’s management to study various alternatives shortly after Expansion III was completed. It soon became apparent that a considerable amount of ore assaying 0.35% copper had to be moved in order to maintain mill feed at the desired 0.54% copper content. New Mill Flowsheet […]
Low-speed Gearless Converter Drive
The first motors of this type were built to drive ball mills in the cement industry, which are very similar to those employed for ore processing. Here, too, the tendency is to build units of ever increasing capacity. In the case of conventional drives with mechanical gearing, this involves correspondingly increasing difficulties. Technical principle A […]
Grinding and Concentration of Conglomerate Copper Ore
The conglomerate ore analyzed approximately 1.2% copper. The specific gravity of the ore was 2.72 and the bulk density was 108 pounds per cubic foot (determined on “as is” ore). The Bond laboratory ball mill work index was determined as 22.0 at 65 mesh. Autogenous Grinding Tests Crude ore was fed manually to the mill, […]
Simulation of Dry Ball Milling using Specific Power
The energy-size reduction relationship was the dominant form of mathematical model used in the description of tumbling mill grinding processes. Typically, in these models some single measure of product fineness (e.g. the 80% passing size, the size modules, the specific surface area) is chosen as the dependent variable and the energy input per unit mass […]