Dec 04, 2018· Therefore, a really energy efficient circuit may mean three stages of grinding instead of only two and each stage can be slightly smaller and more efficient than one big one e.g. a SAG mill (or HRC) followed by a ball mill and with a tertiary Vertimill. These options should at least be considered in the prefeasibility stage to see if the energy ...
AG/SAG and ball mill circuit data is also very poor. Use of equation 2 shows a very different picture, the results being illustrated in Figure 7. This shows that on average the "M" operating work indices of AG/SAG and ball mill circuits are very similar and hence energy utilisation efficiencies are similar. Also
Jan 01, 2005· Ball-Mill Circuit Operation. Very often in SAG circuits, the ball-mill circuit is neglected. In many operations where economics dictate that throughput is worth more economically than the required sace in grind, the focus shifts to throughput so much that the available ball-mill power is not used to the fullest extent.
GrindingExpert™ SAG Mill The GrindingExpert solution will automatically adjust feed rate, mill speed and water addition to reduce upsets, eliminate grind-outs and increase tonnage in SAG / ball mills. Secondary grinding can be optimised as well with automation on cyclones and pumps. This grinding expert solution is an add on to LoadIQ. Benefits
Single stage SAG Mills are very beneficial in reducing CAPEX for plants with a staged throughput approach. When future tonnage is to be increased, the SAG Mill can feed downstream ball milling to boost capacity. Fuller-Traylor SAG/AG Mills range in size from 4.3m through 12.2m in diameter with powers as high as 28,000 kW.
Jan 08, 2016· In this training module, we'll cover the workings of a semi-autogenous grinding mill, or SAG mill, that's designed to be the first stage of a grinding circui...
The ROM SAG mill circuit—a brief description The typical ROM SAG mill circuit is depicted in Figure 1. The circuit is usually closed with either a screen or, more commonly, a cyclone for product size classification. The focus of control can be divided into two parts, viz. the mill and the cyclone. The importance of cyclone performance should ...
A SAG/ball mill circuit using the largest . commercially available ball mill in conjunction with a proven SAG mill . design was selected as the preferred option. This circuit would be .
The results showed that the HPGR-ball mill circuit achieved a 21% reduction in energy consumption over the existing SAG-ball mill circuit at the same P80 grind size of 160 mircons (μm). At a grind of 80% passing 75 μm, the HPGR-stirred mill circuit showed a 34% …
The range of mill sizes and versatile applications allow SAG milling to be accomplished with fewer lines than conventional set-ups. This, in turn, contributes to lower capital and maintenance costs for a SAG mill circuit. Versatile applications . SAG milling extends itself to many applications due to the range of mill sizes available.
In addition, the size distribution and grinding circuit chemistry may impact on the performance of the downstream circuit (Lane, 1999 and Rantanen, 1996). Fully autogenous circuits are attractive due to the elimination of steel media costs. Typically, a SAG mill based circuit (P80 of 106 to 150 um) has media costs of around A$1/t.
John Starkey, P. Eng. has worked in SAG mill hardness testing since 1964 where he worked as pilot plant engineer for A. MacPherson's projects. He invented the SPI and SAGDesign tests. The latter is now acknowledged by our clients to be a world-class method for grinding circuit design, and is accepted by our peers as a standard for ore ...
SAG mill. SAG is an acronym for semi-autogenous grinding. SAG mills are autogenous mills that also use grinding balls like a ball mill. A SAG mill is usually a primary or first stage grinder. SAG mills use a ball charge of 8 to 21%. The largest SAG mill is 42' (12.8m) in diameter, powered by a …
SAG Mill power draw models are used in mill design and grinding circuit modelling to predict how muc h pow er wi... [↓ read more ↓] Alex Doll: modelling: A simple estimation method of materials handling specific energy consumption in HPGR circuits
Jul 20, 2017· ABC closed circuit, Autogenous-Ball-Mill-Crusher. Another similar technique is the ABC open circuit where the crusher product feeds the ball mill rather than the autogenous mill. Crusher product is typical feed to a ball mill using large diameter balls but not much grinding of 20-25 mm ore can be accomplished in an autogenous mill.
The Grinding Circuit optimization Application is the first technology to accurately predict critical SAG Mill performance variables. It then correlates this data to give an accurate picture of conditions inside the mill. This allows mines to reduce downtime in operations by reducing scheduled liner wear inspections and unnecessary changes.
Figure 1 - Overview grinding circuit The Copper Mountain SAG mill is 10363 mm [34 feet] in diameter and 6096 mm [20 feet] long. It is a grate discharge mill with an inside diameter of 10363 mm [34 feet] and a grinding length of 5334 mm [17.5 feet]. The mill is driven by two 8,500 horsepower ABB motors. Figure 2 - The 34' x 20' SAG mill
Further, the SAG mill circuit was characterized by fluctuating feed size of between x. F, 80 =102 to 185 mm. A need for control of the feed size as well as blending ratios was recommended for an efficient operation in terms of throughput and final product size. This could be …
Mill consistent with survey #2 exhibiting a finer SAG mill product (smaller throughput with a pebble crusher running would have been between 631 transfer size) to the ball milling circuit than survey #1 (See Figure 6). and 935 dmtph for the feed size distribution achieved by this blast design.
circuit is shown in Figure1. It is commonly referred to as a SABC circuit, for Semi-Autogenous Ball mill Crusher (SABC). This circuit shows a semi-autogenous grinding (SAG)/ball mill circuit where both grinding mills are in closed circuit, with the SAG mill closed with a crusher to control the amount of 'critical size' material in the circuit.
to be used to predict the SAG mill circuit and ball mill circuit specific energies it is important to ascertain: 1. whether the transfer distributions obey the parallel conditions 2. what the appropriate T80 value should be for a given ore type, circuit configuration, mill geometry and operating condition 10 100 0.01 0.1 1 10 100 1000 size (mm)
A milling circuit employs SABC, SAG mill product is wet screened; - Screen undersize goes into a mil discharge sump and is pumped to cyclones. Cyclone overflow is fed to flotation while cyclone underflow is fed by gravity to the ball Mill for further grinding.
The behavior of the SAG mill circuit is multivariable i.e. exhibit complex interactions and nonlinear behavior between the process variables. It is also dynamic i.e. delay times between variables within the process need to be considered before control actions are executed. Given these challenges, the objectives for acceptable SAG mill operation ...
pebble crushing or low aspect SAG mill circuit where pebble extraction rates are insufficient. Darlot, Jacobina, Driefontein (Surface) Modelling For a new design, the approach taken by OMC is to seek closure between two modelling methods. Typically power base modelling is utilised.
The non-linear behaviour of the grinding mill circuit over a large operating region is not easily modelled by the linear transfer function models. There are a number of nonlinear dynamic models available for grinding mill circuits. These models can be divided into fundamental models and …
considered, such as a primary SAG and secondary ball mill circuit where the individual stages would be ESAG and Eball, and the combined total circuit CEE would be Etotal. In all cases, the specific energy consumption is defined as the motor power consumed relative to the shell of the mill (a.k.a.
Page 769 MINING AND MINERAL PROCESS ENGINEERING, UBC - Vancouver, 6. C. Canada AG AND SAG MILL CIRCUIT SELECTION AND DESIGN BY SIMULATION Dr. S Morrell' and Dr. R D Morrison2
The circuit consists of a 34' x 20' EGL SAG mill, a Raptor 900 pebble crusher and two 24' x 39'6" ball mills. Each mill is equipped with a 2 x 8500HP dual pinion drive system. The plant was designed to process 1585 h mtpof SAG feed. From startup, the mill struggled to meet the required production rates.