Grinding Mills

HOLDTRADE works with FLSmidth who manufactures and designs the entire group of principle milling systems so that our customers can get access to complete mining solutions. Grinding mills are used to break solid material into smaller pieces. There are many different types of grinding mills and many types of materials processed in them.

If you would like to speak with us about Grinding Mills please Call Us at our Mining and Operations office.

The grinding of solid matters occurs under exposure of mechanical forces. After the grinding the state of the solid is changed: the grain size, the grain size disposition and the grain shape.

Grinding may serve the following purposes in engineering:
  • Increase of the surface area of a solid
  • Manufacturing of a solid with a desired grain size
  • Pulping of resources

Ball Mills

Photographs of ball mills

HOLDTRADE works with Fuller-Traylor mills to ensure the most robust design in the industry with ball mill installations through 27' in diameter, which have been manufactured in both trunnion and shell-supported arrangements. A ball mill is a type of grinder used to grind materials like into extremely fine powder for use in mineral dressing processes, paints, pyrotechnics, and ceramics.

Ball mills are cylindrical and are used to grind or mix ores, chemicals, ceramic raw materials and paints. They are used extensively in the Mechanical alloying process in which they are not only used for grinding but for cold welding as well, with the purpose of producing alloys from powders.

How ball mills work

Ball mills work by rotating around a horizontal axis, partially filled with the material to be ground plus the grinding medium. Different materials are used as media, including ceramic balls, flint pebbles and stainless steel balls. An internal cascading effect reduces the material to a fine powder. Industrial ball mills can operate continuously, fed at one end and discharged at the other end.

SAG Mills

Photographs of SAG Mills

Using Fuller-Traylor HOLDTRADE can provide customers with SAG/AG mills ranging in size from 18' through 40' in diameter with powers as high as 30,000 hp. These mills feature hydrostatic lubrication and can accommodate either a geared or gearless drive arrangement and are typically grate discharge and use metal liners.

A large number of SAG Mills are supplied to the mining industry, of which 25% are of the innovative open-end discharge design supported on slipper pad bearings.

Semi-Autogenous Grinding mills utilise steel balls in addition to large rocks for grinding, with a minimal ball charge of 6 to 15%. SAG mills are characterized by their large diameter and short length, and are primarily used in the gold, copper and platinum industries with applications also in the lead, zinc, silver, alumina and nickel industries.

How SAG Mills Work

A rotating drum throws large rocks and steel balls in a cataracting motion which causes impact breakage of larger rocks and compressive grinding of finer particles. Attrition in the charge causes grinding of finer particles.  The inside of the mill is lined with lifting plates to lift the material inside up and around the inside of the mill, where it then falls off the plates and falls back down.

What's the Difference between SAG Mills (Semi-Autogenous) and AG mills (Autogenous)?

  • Autogenous mills use the ore itself is the grinding media.
  • Semi-autogenous grinding uses a minimal ball charge in the range of 6-15%, and is primarily used in the gold, copper and platinum industries but also in lead, zinc, silver, and nickel industries.