About Anupam

In 2008, Anupam obtained a Chemical Engineering from the Bapatla Engineering College in India. This University Level Degree was followed, in 2010, by a Master's Degree, in Metallurgical Engineering from The University of Utah.

Gangue Depressant in Molybdenum Flotation

Sodium cyanide and Nokes reagent are commonly used depressants to reject iron, copper, and lead sulfide minerals for the flotation recovery and upgrading of molybdenite concentrate. With the ever increasing cost of reagents and more stringent regulations, it is necessary that these depressants are used as efficiently and effectively as possible. Therefore, a study was undertaken to investigate the effects of concentration and conditioning time of two depressants—sodium cyanide and Nokes reagent—at different levels of pH on the rejection of sulfide impurities from the molybdenite concentrate. This paper discusses the experimental methods used and the results obtained to date on this ongoing investigation.

A representative sample of the first-stage cleaner flotation feed in the mill was obtained for this study. The sample assayed 6.2 percent MoS2, 13.5 percent FeS2, 0.108 percent Cu, and 0.026 percent Pb. The bench-scale flotation tests were performed in a 4.5-liter Denver D12 flotation machine. Concentrates were collected at cumulative times of 3, 5, and 7 minutes of flotation, and flotation products were assayed for MoS2, Cu, Pb, and FeS2.

Three series of tests were performed to investigate the following:

  1. effect of conditioning time of depressants,
  2. effect of pH, and
  3. effect of depressant addition rates on the

How to Control a SAG Grinding Mill Circuit

Autogenous and semi-autogenous grinding have experienced renewed interest as efforts to reduce operating and capital costs have increased.

As a result, the mill operator is faced with new equipment perhaps ten times as large as was common in the sixties and new circuit designs with different operating characteristics. No longer can he grab a handful of mill discharge to estimate the size distribution and viscosity or cut a liter sample to determine the pulp density. The operator is separated from the mill discharge by a sump or screen 5 or 6 meters across. He is fortunate if he can even see what is coming out of the mill, let alone get a reasonable sample. The sound and feel of the mill has changed. The ampere meter on the drive motor is probably a hundred meters away in a control room. Figures 1 and 2 illustrate typical grinding circuits and instrumentation. What, then, can we in the Engineering and Construction Industry provide the operator to assist him in operating the circuit somewhere near its maximum efficiency?control grinding circuits screen oversize

To answer this question, let us redefine the goal of the mill operator. The goal of

Placer Gold Mining

The location of a prospect usually results from some physical evidence of the presence of gold and/or past mining activity. Any earlier activity that may have produced gold from the prospect, should be investigated before making the trip.

The initial reconnaissance should attempt to verify a near-surface presence and then make observations concerning the geomorphic characteristics that relate to placer gold accumulation. Estimates of the probable depth, breadth and length of mineable gravels can be made from the surface by the experienced placer mining engineer. With this information, he can speculate on whether there is a viable prospect to be pursued. The placer mining engineer should be experienced in panning samples found in shallow diggings or from existing pits. This will give him immediate indications of gold presence without fear of “salting” by an over-ambitious promoter of the project. The same capability of panning is important during the other sampling phases. A thorough knowledge of logging and calculating the results is essential to proper evaluation of the deposit’s tenor.

Evaluation Methods

Depending upon the character of the prospect such as river, benches, terraces, jungle, the type of equipment to conduct sampling of the deposit must be determined. In most cases, the

Mineral Processing Plant Sample Equipment

Coarse-ore dry sampling of the type found in primary and secondary crushing systems prior to processing, often requires sampling large flow rates containing 2″ to 6″ particles. The cutter width must be adjustable, with the minimum opening being 2½ to 3 times wider than the largest particle (Figure 1). The cutter blades should enter the flow stream perpendicularly to the trajectory. The cutter discharge chute should be adequately sloped to assure free flow. Typically, this is 50° from the horizontal for a stream containing particles, 60% of which are larger than 1″, with a total surface moisture of less than 10%. When the sample flow is less than 20% coarse material, or if the surface moisture is greater than 10%, a cutter slope of 60° is required.

When sampling large flows (800 to 10,000 TPH) it is necessary to attach a thrust wheel behind the cutter to absorb the impact from the flow. The wheel assembly must be positioned out of the trajectory (Figure 2). If a baffle plate is used, it must also be supported by wheel assemblies. A problem often encountered when dry sampling is that the sample may be contaminated from dust or larger particles falling into the

Cone Crusher Operating Variables

Although past investigations have been conducted to determine crushing relationships, no program which covered a broad range of crushing conditions had been conducted. The previous studies appear to concentrate on small segments of the overall picture and did not fullfill our desired information objectives. Due to the broad range of variables utilized in a production size crusher, is believed to be the most comprehensive study of its kind as of this date.

The principles developed by the Symons brothers in 1925, when they patented the cone crusher as we know it today, are still being used in the machine known as the Symons Cone Crusher. During the development of this novel crushing concept, a technique known as the fall of material (called the Bouncing Ball Theory by some) was used to determine an idea as to the proper head angle, eccentric and speed of eccentric rotation. The final variables used for the Symons Cone Crusher design were, therefore, the logical conditions to start with and use as a reference against which other variables could be compared.

Other tests, conducted in the field and at the MRTC, have confirmed that the eccentric speed should not be reduced below the speed normally used.

Zinc Roasting Furnaces

Roasting Ferruginous Zinc Sulfide Ores

Mr. J. B. Keating was developing an electrolytic-zinc process for application to the ores of the Bully Hill mines of the General Electric Co. These ores consist of blende and pyrite so finely crystallized and so intimately mixed that no mechanical separation of the individual minerals had been found possible. The ore was reduced to about 60 mesh and roasted in a hand-rabbled reverberatory furnace preparatory to leaching with sulfuric acid. The extractions obtained were quite irregular, varying from a minimum of about 70 per cent, to a maximum of about 90 per cent. This irregularity led to the construction of a small electrically heated roasting furnace, and to the study of roasting under definitely controllable conditions. From time to time, these studies have been extended to other ores. Several commercial-plant operators profess to have gained useful information from the results of these studies and it is hoped that their usefulness may be extended by this publication.

Experimental Electric Roasting Furnace

The furnace used for experimental work is shown in Fig. 1. One fireclay sagger, or pot, was set within another and the space between the two filled with Silox heat insulation. The hearth

Mine Ventilation EXAMPLE

The Copper Queen mine is composed of seven divisions which are operated through the following shafts:

The workings of the different shafts are connected by motor-haulage drifts on the even numbered levels. The general location of the orebodies and workings is illustrated by the vertical projection of orebodies of the district as shown in Fig. 1.

The Uncle Sam, Southwest, and Czar workings have many connections to the surface through raises and extensive cracks that were caused by moving ground. These divisions are cool and are ventilated entirely by natural means.

The Holbrook is ventilated partly by natural and partly by artificial ventilation, while the Spray, Gardner, Lowell, and Sacramento are ventilated entirely by mechanical means.

In some of the divisions mentioned above a considerable quantity of air exhausts through shafts of adjoining properties.

mine shafts


Conditions under Natural Ventilation

Several Mine Fires Occurred

mine ventilation

During the last few years several mine fires menaced both life and property. The most serious mine fire was that of the Lowell, which occurred during 1911. The district where the fire originated was between the 1,000

Mine Roof Stresses & Support

The stresses, in the simplest structures are often those we find most difficult to analyze. The most complex condition in mine stresses is found in simple tunnels where the roof, the sides, and the floor are a monolith. The functions of the parts are like the parts themselves not distinct and specialized, and the problems to be solved are like those in a metal structure with riveted joints or a redundancy of bars.

This difficulty explains perhaps why the condition has not been treated. But just because it cannot be discussed in its entirety is no reason why it should be treated as an action of parts with specialized functions as a roof beam with supports and a foundation. The problem cannot be ignored on the ground that it is not of sufficient importance to warrant careful consideration, because conditions of complete monolithism, of which the tunnel is the type, are found materially unchanged in room-and- pillar and in longwall work.

This unity between roof, sides, and floor, which to the coal miner is a difficult conception, really deserves a scientific appellation, and perhaps holoid (from holos, whole, and eidos, form) will serve the purpose as well as any other.

In a simple

Solvent Extraction Equipment & Design Parameter

Parameters Provided by DPG Research & Development Division

Once the process route and correct Solvent Extraction Equipment type have been decided, the following are the basic design parameters that R & D can provide:

  1. Reagent and Diluent choice and composition. The composition of the organic phase and of the aqueous input streams enable the isotherm to be determined.
  2. Equilibrium Isotherm, Stage Efficiencies, Number of stages. Using single stage efficiencies the equilibrium isotherm is converted into the pseudo-equilibrium isotherm and the number of stages predicted using the McCabe Thiele construction.
  3. Solution Compositions for Mass Balance. These will have been determined by the McCabe-Thiele construction performed above.
  4. Mixer Residence Time for given impeller type. This is dependent on the kinetics of the mass transfer between phases. The mixer residence time together with the organic: aqueous operating ratio fixes the mixer dimensions according to the formula given in section 3. For typical values for copper systems of this and other parameters see the comparison table.
  5. Organic/Aqueous operating ratio. The operating O/A ratio is the volume flow ratio of total organic and total aqueous streams entering the mixer box. It will normally be in the region of 1:1 so as to minimise


While assaying some copper carbonate ore from the Frazer claims, Similakameen, B. C., I noticed that on parting the gold button a deep orange solution was formed. The button gave off pink bands in the nitric acid, which became deep orange at a short distance from it; and as it traveled over the surface of the porcelain dish, it left a deep orange track behind. As the button brightened in the cupel, it appeared to have a bronze color; but I have since found that when amarillium is in large excess of the gold, the button is a very dark gray. The button parted easily. To the orange solution I added a salt (NaCl) solution, shook in a silver test-bottle, and filtered. With H2S I obtained a precipitate, which I supposed due to platinum. However, on further tests, it did not act like a platinum-precipitate, but fused and united somewhat with the surface of the porcelain cup. On testing it further with soda I obtained a button of metal (amarillium). This strange result led me to a careful examination of the ore and a repetition of the assays, remembering the highly emphatic instructions of my talented instructor in assaying,

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