Ore Feed Size * Work Index Hardness: Crushing & Mill Tonnage
The single most common reason for an increase or drop in the production of fines is the WORK INDEX of the ore. If you remember, the work index of the ore is a method of measuring the degree of hardness. As the ore becomes harder the fracture lines in the rock become cleaner or sharper […]
Moon Mining Helium 3
Feeder Control -Ore Feed Size and Mill Tonnage
One area of major importance for the identification of impending problems are the feed belts. By visually estimating the PHYSICAL CHARACTERISTICS of the ore it is possible to have advance warning of change in many of the variables. Feed size is the most apparent, if the crush is supposed to be minus 3/8 of an […]
Operating a Grinding Circuit -How to Operate
What I would like to do now is expand upon the grinding theory involved. Bring all of the earlier information together and show you how it relates to the operation of a mill and make you capable of Operating a Grinding Circuit correctly. Then I will explain the differences between Rod mills, Ball mills, SAG […]
Specific Gravity to Density of Pulp or Slurry
As mill operators you don’t have to worry about the mathematics of a Specific Gravity to Density conversion. These specific gravities have all been worked out and are presented in a table form. You simply consult the line that represents the specific gravity of the ore that you are working with, match it with the dissecting line […]
How to Find and Determine the Specific Gravity of a Rock
In the method we use to How to Find and Determine Specific Gravity of Rocks (some call it Specific Density because they don’t know better!), we’ll use simple equipment. What is required to make this measurement is a weight scale, and the list of the different minerals SPECIFIC GRAVITIES. What specific gravity is, is the mass […]
LSSM = Low Speed Synchronous Motor Drive Operation
In the world of mining and milling the “electrical term” LSSM stands for “Low Speed Synchronous Motor” and usually means a mill where the motor rated speed is in the range of 10 RPM, the same speed as the mill turns. A high speed motor can run at 900 RPM and uses a gearbox to turn down the speed. […]
Effect of Water & Density on Grinding Mill
The Time that the ore spends in the grinding mill is called, RETENTION TIME. This is a very important variable, the longer the retention time, the more the ore comes in contact with the rods, the better and finer the grind becomes. To understand this important control it must be remembered that any volume that […]
Grinding Mill Gear Assembly
We will begin with the mill’s bull gear assembly and work towards the motor, The BULL GEAR, sometimes called the RING GEAR is designed to turn the mill transforming the energy of the motor into motion for the mill. By mill we refer to Ball Mills, Rod Mills and SAG Mills. Anything gear and pinion […]
Leaking Mill Shell Bolts
Dealing with leaking Mill Shell bolts is common enough an occurrence in most concentrator plants. All that an operator can really do about it is to keep the problem to a minimum. The cause of the bolts leaking is running the mill with a density that is to light or feed that requires a high impact to […]