INTRODUCTION Glencore recently completed construction of a new 70,000 tonnes per day copper concentrator near Cusco, Peru. Plant startup was accomplished during the last quarter of 2012. Comminution is accomplished by primary crushing, SAG milling and pebble crushing followed by ball milling.
Obviously, the SAG mill is consuming more and the ball mill less power than was predicted by the empirical method, but the overall total is % of the predicted total. Examples. The Hemlo gold project of TeckCorona (1000 mtpd) provides an example of mill sizing using the empirical calculation method alone.
ABSTRACT The design of the 40foot diameter SAG mill installed at the Cadia Gold Mine, New South Wales Australia, followed after two years of extensive laboratory and pilot plant testwork. This showed the Cadia ores to be hard and competent n ecessitating the use of both a variable speed mill drive and pebble crushing.
The purpose of this study is to investigate and simulate the optimal operating conditions of a ball mill in a copper processing plant. The actual operating conditions in the intended mill are ...
The implications for the equipment sizing of the downstream ball mills can be significant (Patzelt et al., 2006). Schönert (1988) estimated that replacing existing circuits with HPGRball mill circuits could increase circuit capacity by 1225%, and reduce energy by 1020%. However, for this to be achieved the HPGR must produce at least 10% ...
S Nadolski, R Haycock, K Li, S Seiler, A Kumar SAG Conference Vancouver, Canada September 22 26, 2019 ABSTRACT A comprehensive energy study was carried out for the Red Chris mill, which processes coppergold ore at a rate of 30,000 tonnes per day (t/d) and is located in Northern British Columbi...
In this example, the OWi of the SAG mill was found to be 30% higher than the ball mill, thus suggesting that the SAG mill was less efficient than the ball mill. The apparent inefficiency of SAG mills when using Bond analysis is widely understood to be due to the difference in the slopes of the size distributions. In contrast, when the SSE75 was ...
Grinding and Flotation. Fine ore at minus 19mm (¾") sizing is fed at a controlled rate into the opencircuit 2600mm x 3960mm (8'6 x 13'0) Hardinge rod mill at an average feed rate of 2,106 STPD or STRH. Rod mill discharge at a nominal size of minus 16 mesh and a pulp density of 75 percent solids combines with ball mill discharge ...
A total of 120 t of Cristalino ore was prepared and sent to CIMM, where it was crushed and screened prior to grinding tests. The processing equipment included a m (8′) diameter by m (2′) length AG/SAG mill equipped with a 20 kW motor, a cone crusher, a m (3′) diameter by m (4′) length ball mill equipped with a 15 kW ...
Overall power for the comminution circuit (SAG plus ball mills) base on a maximum ball mill Wi of /t (ave. /t plus one standard deviation of 1 kWh/t) indicated a maximum specific ...
Isa Mills: <" grinding balls are recommended. The Isa Mill is more efficient when using small media ( highchrome steel balls). Rotary Mills: Small cylpebs (<1") are effective in ultrafine wet regrinding operations. SAG Mills: 4"6" forgedsteel balls are recommended. Cast balls are not agood choice.
The ball mill wear data reflected a factor on the Bond equation consistent with Arts observation above. I also like the Molycop equation Levi has discussed for ball mills although it does seem to reflect slightly higher wear rates than what we see in circuits where a ball mill follows a SAG mill.
The SABC circuit design is to accept minus 8″ run of mine ore from a 12,000 ton silo. Two Forano pan feeders discharge from the silo onto a 48″ belt which feeds the 32′ x ′ mill. The mill is powered by two 5500 hp motors. Nominal mill speed is (78% critical) with a top speed of
In this case, an AG or SAG mill may be appropriate. For smaller throughput scenarios, a threestage crushing plus rod mill plus Vertimill may make the most sense. It all depends on the ore ...
Then, in the late 1980s when the price of copper rose quickly from a low of /lb to a high of /lb, this substantial increase in price further fuelled the industry demand for larger diameter SAG mills, with mill power quickly doubling from 15,000hp to 30,000hp (11,00022,000kW). As SAG mills grew in size and number, so did the size and ...
SAG mills, rod mills and ball mills are the classical pieces of grinding equipment employed in gold recovery plants. There is an increasing trend to employ SAG mills (semiautogenous mills) in place of secondary and tertiary crushing and primary grinding. The most common type of rod mill is the overflow mill. There are two typed of ball mills used.
Furthermore, the SAG mill circuit indicated varying feed sizes ( xF,80 =102 to 185 mm) which could be rectified by closer monitoring and control of ratios for the SAG mill feeders drawing the ...
Copper Mountain first feed to the SAG mill occurred in late May, 2011. The circuit began ramp up in midJune of that year, with more consistent operating run times on the SAG and Ball mills. Plant throughput in the first months was quite variable with throughput tonnage greater than 40,000 tons one day and less than 25,000 the next on some ...
> Common in cement mills > Large ball mills > Malleable Iron: cast as white iron, then malleabilised, or heat treated, to impart ductility. Consists of tempered graphite in an a ferrite or pearlite matrix Microstructure of Malleable Iron Source: Perez and Stameroff (2003)
With high aspect ratio SAG mills total charge to ball charge ratio should be greater than 2 (up to ) for a coarse mill feed (say F80 > 110 mm). If the mill feed size is fine, say 50 mm or 30 mm, then you are looking at a total charge to ball charge ratio of about
One is dominant in SAG other one is more dominant in ball milling. As all we know SAG uses mostly impacts, however ball uses both impact and good amount of abrasion that is supposedly take all the added collector from the surface. Single categorization for tumbling mills as impact is quite insufficient. In addition, from this article it is ...
In order to make a good comparison of capital costs, it was decided to compare total installed costs from semiautogenous mill feed to grinding circuit product (flotation feed) for a typical 36,364 mtpd (40,000 stpd) semiautogenous ball mill circuit treating a copper porphyry ore.
CERAMIC LINED BALL MILL. Ball Mills can be supplied with either ceramic or rubber linings for wet or dry grinding, for continuous or batch type operation, in sizes from 15″ x 21″ to 8′ x 12′. High density ceramic linings of uniform hardness male possible thinner linings and greater and more effective grinding volume.
We're looking at optimizing some of the reagents and balancing feeds between the SAG mill and the ball mills that currently are a bit of a bottleneck. We can hit as high as 45,000 tonnes per day.
Whereas 30 years ago the rule of thumb for designing AG/SAGBall mill circuits was to split the total installed motor capacity 50:50 between the AG/SAG and ball mill circuits, Tozlu and Fresko's ...
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