Flowsheet Description

The circuit grinds Taconite that has been pre-concentrated in a Cobber Magnetic Drum, thus the feed stream is labeled Cobber Conc. For those unfamiliar with this process, a Cobber is basically a high-intensity magnetic drum separator, designed to operate with relatively coarse ore particles. The Cobber Concentrate enters the circuit through a sump, which regulates the flow and solids content to the feed to a Ball Mill. Different than a standard closed grinding circuit with classification, this circuit contains a concentrating stage between the milling and classification stages. This concentration is accomplished by a bank of Wet Magnetic Drums, treating the Ball Mill Discharge. The solids content in the feed to the drum must also be regulated by a sump, since the Ball Mill discharge solids content is too high for this process. The tailings of the Magnetic Drum are discarded. This makes a lot of sense since regrinding particles that contain little or no Iron is definitely not cost effective. The magnetic drum concentrate is fed to a hydrocyclone classifier cluster, through a sump, again to regulate the solids content. The hydrocyclone underflow is recirculated, with the circuit feed, back to the mill. The overflow stream is the product of the grinding circuit, and this undergoes further concentration and screening.

Note: when drawing the magnetic drum icon you will have to reflect the icon if you want your flowsheet to look similar to the one in the figure. Also, if you would like to see this flowsheet being drawn you can use your ScreenCam Player that was installed with your Modsim, CD ROM version 3.2. Just run scplayer from your Programs -> ModsimV32 Student shortcuts.Click on the upper-left icon on the ScreenCam player window frame and choose File Open... Load the Mod7-A1drawing-smallfairlane.scm file from the Course directory in the Modsim installation directory. Push Play. Unfortunately, ScreenCam files are too large to deliver over the internet, and we have abandoned this tool in favor of viewlets.