AG/SAG mills for a given feed size distribution and feed rate (Morrell and Morrison, 1996). Hence when using JKSimMet in a design situation, the dimensions of the AG/SAG mill are adjusted until the load in the mill reaches 25 % by volume when fed at the required feed rate. The model predicts the
highly interactive form of this feed-back loop SAG mills can be dif-ﬁcult to stabilise. Stabilisation control can be achieved with a good control system, holding the mill within a window of pre-deter-mined operating conditions. For a ﬁxed mill ﬁlling and mill speed, the product size will change for a target feed rate as the feed type ...
Two new SAG milling models are developed in this work, able to predict power or specific energy consumption, including the usual design variables such as mill size; balls charge level, solids concentration in the SAG mill feed and % of critical speed, but adding a variable that represents the feed size …
Feed size effects what size is important? historically, Mine-to-Mill has – focussed on blasting alone – generation of more fines • pass through SAG mill onto ball mill circuits • higher throughput (e.g. 10% to 30%) • coarser grind size (possibly) fine <25mm medium 25 - 75mm coarse >75mm
SAG mill itself and not on the test work program. Stated another way, money invested in a large SAG mill is an investment that can produce handsome returns if extra production is needed or simply to give the mine the option to mill the hardest ores at design throughput rates.
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 28 MW (38,000 HP) motor.
These equations are used by SMCC Pty Ltd to estimate the specific energy of AG/SAG mills under all normal operating conditions, eg ball load, mill speed, feed size and ore hardness and for all ...
While AG mills operate without a ball charge, SAG mills use a grinding media charge of normally 3 % - 12 % for comminuting the feed material. The maximum feed size is between 200 mm and 500 mm. The AG/SAG mill is normally installed upstream of a tube mill operating in closed circuit with hydrocyclones.
Relation between Sag mill solid and product P80! Both are dependent on feed size. Dependent on Volume % solids in SAG mill. Dependent on ball charge volume. Hardness of ore. Recirculation load. Dependent on P80% size. All other parameters are secondary. In general Sag mill solids are kept at 70% by wt. Operating grinding circuit is an art.
DESIGN OF THE 40 FOOT DIAMETER SAG MILL INSTALLED AT THE CADIA GOLD COPPER MINE of the engineering a flowsheet review was undertaken. This led to a ... A SAG mill feed size (F 80) ...
The feed size for these mills is limited to the maximum size that can be practically conveyed and introduced into the large mill feed chutes. And the product of the large AG/SAG grinding is either a finished size ready of processing, or an immediate size for further grinding in a ball mill, pebble mill, VERTIMILL® or a stirred media detritor ...
The PTI study focussed on ball mill limited material from the Apensu open pit. Following a benchmarking study of all blasting, crushing and grinding practices in January 2009, PTI recommended changes in both blasting and crushing conditions in order to generate a finer feed size to the SAG mill.
Every mining operation has a unique grinding process. has experience of over 8,000 grinding mills globally, including manufacturing and delivering the largest SAG/AG mills in the world. Our experts welcome the opportunity to assist you with circuit and circuit control design as well as start-up, operation, and optimization of your mill.
Modelling SAG milling power and speciﬁc energy consumption including the feed percentage of intermediate size particles M. Silva, A. Casali⇑ Mining Engineering Department, Universidad de Chile, Beauchef 850, Santiago 8370448, Chile
Model Predictive Control for SAG Milling in Minerals Processing | 5 Model Predictive Control on a SAG Mill and Ball Mills The solution for the SAG Mill is an adaptive controller which controls mill load using direct mill weight measurement or indirectly from bearing oil pressure.
Table of Contents Autogenous Grinding CircuitsSAG vs Ball Mill AdvantagesAG & SAG Mill Grinding Compared – Which is BestTesting for Product Size Size reduction is the most expensive operation in most mills. Crushing and grinding usually require the greatest portion of capital costs and often make up 60-70 percent of total mill operating costs as shown in Figure 1.
Oct 12, 2017· SAG mill make use of steel balls included with some large and hard rocks for grinding. These mills utilize the balls in making the large fragments of materials broken into pieces. The ball charge of a SAG mill is about 9% to 20%.This process takes place inside the large rotating drum of SAG mill which is filled with balls partially.
Feed Size, F80: Primary crushed ore is mandatory to feed any SAG mill. Typical feed size range is 80% passing 130 to 160 mm. Softer ores will be a little finer but the finer size is not sustainable when the ore becomes hard. Pre-crushing to finer sizes enhances throughput as does crushing of pebbles from the SAG mill (usually minus 60 mm).
After closed-circuit secondary crushing, the SAG mill feed 80% passing (F80) size was 25 mm to 30 mm. Installed grinding power is split equally between the two mills with the SAG mill fitted with a variable speed drive (VSD). SAG discharge screen oversize ('pebbles' or 'scats') was …
As all ex- primary crusher ag/sag mill feed size distributions are the result of how in-situ rock has been blasted and subsequently treated by the primary crusher, it is reasonable to expect that by changing how blasting is carried out and how the primary crusher is operated …
2 THE APPROPRIATENESS OF THE TRANSFER SIZE IN AG AND SAG MILL CIRCUIT DESIGN ABSTRACT The AG/SAG circuit discharge P80 is now increasingly referred to as the "Transfer Size…
stage ball mills, rod mills or AG/SAG mills when calculating power according to the Bond Third Theory method. Rod mill and AG/SAG mill products are similar and tend to be not as steep as a 0.5 slope when plotted on log-log paper. This is because the particle size distribution (PSD), these mills
SINGLE STAGE SAG/AG MILLING DESIGN ABSTRACT Single stage semi-autogenous / autogenous (S/AG) milling has become a common design for a variety of ore ... The feed size must be realistic as an inappropriate particle size distribution (PSD) ... The SAG mill model in the JKSimMet software has not been shown to accurately reproduce the performance
The mill product can either be finished size ready for processing, or an intermediate size ready for final grinding in a rod mill, ball mill or pebble mill. AG/SAG mills can accomplish the same size reduction work as two or three stages of crushing and screening, a rod mill, and some or all of the work of a ball mill.
Feb 12, 2018· The capacity of the SAG mill is related to lots of factors such as feed size, size distribution, discharge size and grindability, etc., and it should be confirmed according to the actual situation. SM40*14'——means it is a dry mill.
USING THE SMC TEST® TO PREDICT COMMINUTION CIRCUIT PERFORMANCE ... efficiency factor which represents the influence of a pebble crusher in AG/SAG mill circuits. "Coarse" in this case is defined as spanning the size range from a P80 of 750 ... energy between open and closed crushing to reach the nominated ball mill feed size. This assumes ...
The feed size distribution together with the ore characteristics (hardness, lithology, alterations, etc.) are the most important factors affecting the SAG mills performance.