Progress report on the use of small electric motors for (1) cutting ensilage, (2) sawing wood, (3) grinding feed.

Mode of access: Internet.

Surface arrangements at reduction works : ; Ore dressing and milling ; Fine grinding ; Sampling ores ; Roasting and calcining ores ; Hyposulphite lixiviation ; The chlorination process.

Includes index.

The mechanician, a treatise on the construction and manipulation of tools, for the use and instruction of young engineers and scientific amateurs; comprising the arts of blacksmithing and forging; the construction and manufacture of hand tools, and the various methods of using and grinding them; description of hand and machine processes; turning and screw cutting; and the various details of setting out work incidental to the mechanical engineer's and machinist's art.

Mode of access: Internet.

Operator's manual : grinding machine, cylinder head (Cedar Rapids Engineering model 860), FSN 4910-889-2051.

"February 1969."

Operator's manual : grinding kit, valve seat, electric 35 degree angle type concentric drive, 1/4 horsepower, AC/DC, single phase, 115-volt, 14000 RPM rated no load speed (K.O. Lee Company model P300BB) (4910-060-9983) and (K.O. Lee Company model P300BB-M2) (4910-473-6437).

"February 1965."

Operator's manual : grinding kit, valve seat, electric, 35 degree angle, concentric drive, driver, AC/DC, 115-volt, 7,500 RPM rated no load speed (Albertson and Company model 1712-M) (4910-060-9983).

"June 1965."

Organizational maintenance manual (including repair parts and special tools lists) : milling-grinding-drilling-slotting attachment, 115/230-volt, 60-cycle, single-phase, 1/3 horsepower (Dumore Company model 827401) ...

"January 1965."

Operator's manual : grinding machine, machine tool attachment, internal and external grinding, 5" maximum external diameter wheel, 1/4" minimum internal diameter wheel, 4,600 to 42,400 rpm spindle speed, 1/2 hp, AC/DC, 115 V, 60-C, single phase (Dumore series 5) ...

"October 1967."

Operator's manual : grinding machine, machine tool attachment (U.S. Electrical Tool Co. model HLGE-12) (3460-243-9607).

"November 1965."

Operator's manual : grinding machine, valve face, bench mounting, 9/32 inch to 11/16 inch chuck, 0 to 45 degree valve, face angle adjustment, 115-volt, AC/DC, 60-cycle, single phase (Cedar Rapids model "KWIK-WAY" KK) (4910-540-4679).

"6 October 1967."

Performance of small hammer and roller mills for grinding livestock feed

Mode of access: Internet.

A liberation model for comminution based on probability theory

Mineral processing plants use two main processes; these are comminution and separation. The objective of the comminution process is to break complex particles consisting of numerous minerals into smaller simpler particles where individual particles consist primarily of only one mineral. The process in which the mineral composition distribution in particles changes due to breakage is called 'liberation'. The purpose of separation is to separate particles consisting of valuable mineral from those containing nonvaluable mineral. The energy required to break particles to fine sizes is expensive, and therefore the mineral processing engineer must design the circuit so that the breakage of liberated particles is reduced in favour of breaking composite particles. In order to effectively optimize a circuit through simulation it is necessary to predict how the mineral composition distributions change due to comminution. Such a model is called a 'liberation model for comminution'. It was generally considered that such a model should incorporate information about the ore, such as the texture. However, the relationship between the feed and product particles can be estimated using a probability method, with the probability being defined as the probability that a feed particle of a particular composition and size will form a particular product particle of a particular size and composition. The model is based on maximizing the entropy of the probability subject to mass constraints and composition constraint. Not only does this methodology allow a liberation model to be developed for binary particles, but also for particles consisting of many minerals. Results from applying the model to real plant ore are presented. A laboratory ball mill was used to break particles. The results from this experiment were used to estimate the kernel which represents the relationship between parent and progeny particles. A second feed, consisting primarily of heavy particles subsampled from the main ore was then ground through the same mill. The results from the first experiment were used to predict the product of the second experiment. The agreement between the predicted results and the actual results are very good. It is therefore recommended that more extensive validation is needed to fully evaluate the substance of the method. (C) 2003 Elsevier Ltd. All rights reserved.

Determination of lifter design, speed and filling effects in AG mills by 3D DEM

The power required to operate large gyratory mills often exceeds 10 MW. Hence, optimisation of the power consumption will have a significant impact on the overall economic performance and environmental impact of the mineral processing plant. In most of the published models of tumbling mills (e.g. [Morrell, S., 1996. Power draw of wet tumbling mills and its relationship to charge dynamics, Part 2: An empirical approach to modelling of mill power draw. Trans. Inst. Mining Metall. (Section C: Mineral Processing Ext. Metall.) 105, C54-C62. Austin, L.G., 1990. A mill power equation for SAG mills. Miner. Metall. Process. 57-62]), the effect of lifter design and its interaction with mill speed and filling are not incorporated. Recent experience suggests that there is an opportunity for improving grinding efficiency by choosing the appropriate combination of these variables. However, it is difficult to experimentally determine the interactions of these variables in a full scale mill. Although some work has recently been published using DEM simulations, it was basically. limited to 2D. The discrete element code, Particle Flow Code 3D (PFC3D), has been used in this work to model the effects of lifter height (525 cm) and mill speed (50-90% of critical) on the power draw and frequency distribution of specific energy (J/kg) of normal impacts in a 5 m diameter autogenous (AG) mill. It was found that the distribution of the impact energy is affected by the number of lifters, lifter height, mill speed and mill filling. Interactions of lifter design, mill speed and mill filling are demonstrated through three dimensional distinct element methods (3D DEM) modelling. The intensity of the induced stresses (shear and normal) on lifters, and hence the lifter wear, is also simulated. (C) 2004 Elsevier Ltd. All rights reserved.