Comminution is a critical component of most mineral processing flowsheets and serves several purposes, including:

• Liberating valuable minerals that are locked within waste rock
• Increasing available surface area for chemical reactions
• Producing particles within a particular size range to meet product specifications

To properly evaluate the crushing and/or grinding characteristics of a material, Hazen engineers first consider the size distribution, shape, and nature of the feed material. In addition to a full complement of laboratory and pilot-scale size-reduction equipment, we also have the necessary classification and particle size determination facilities. Working with the Mineralogical Laboratory, we develop and optimize size reduction flowsheets.

Comminution Descriptions and Costs (Cost, US$)

Each cost per test listed in this section includes sample preparation, engineer oversight, and reporting (no add-ins). Sample disposal or shipping costs are not included in the cost per test. For larger sample quantities (greater than 4 times the sizes listed in the following text), please Contact us for pricing.

Breakage Characterization – JKTech Procedures: full drop-weight test procedure, requires 80 to 100 kg of minus 4 in. (100 mm) material: $6,000

• This test determines the energy vs. breakage distribution function for five ore sizes from 13 to 63 mm and uses these functions to determine crusher performance and autogenous/semiautogenous milling characteristics. These ore-specific parameters are used in grinding circuit simulation and modeling using the JKSimMet software.

SAG Mill Comminution (SMC) Test: requires 15 kg of ¼ core or 20 kg of minus 2 in. (50 mm) rock: $2,500

• This test uses the same procedure as the full drop-weight test, except it uses only one size fraction at five energy levels.

Bond Rod Mill Grindability: requires 25 kg of minus ½ in. material: $1,000

• This test determines the Bond Rod Mill Work Index, which can be used with Bond’s Third Theory of Comminution to calculate net power requirements of sizing rod mills. The test is a closed-circuit, dry grindability test, is run in a standard rod mill, and can be performed at sizes ranging from 4.76 mm to 210 microns. The normal finishing size is 1.2 mm.

Bond Ball Mill Grindability: requires 10 to 15 kg of minus 6 mesh material: $1,000

• This test determines the Bond Ball Mill Work Index, which can be used with Bond’s Third Theory of Comminution to calculate net power requirements for sizing ball mills. The test is a closed-circuit, dry grindability test, and is run in a standard ball mill. Tests may be conducted at closing sizes from 48 to 400 mesh (300 to 37 microns). The standard closing size is 100 mesh Tyler (150 microns). 

Bond Abrasion Test: requires 1.6 kg material, ¾ by ½ in.: $450

• This test determines the Bond Abrasion Index, which can be used to determine steel media and liner wear in crushers, rod mills, and ball mills. The equipment consists of a rotating drum, into which the dry ore sample is placed, with an impact paddle mounted on a center shaft rotating at a higher speed than the drum. The paddle is made of a standard alloy steel hardened to 500 Brinell. The abrasion index is determined from the weight loss of the paddle under standard operating conditions.

Comminution Work Contracted to Outside Laboratories

Please Contact us to learn more about requirements and pricing for the services in this section.

• CW_i Test (Bond Impact Work Index), FLSmidth (Salt Lake City, UT)
• Los Angeles (LA) Abrasion Test, Geocal, Inc. (Centennial, CO)
• Unconfined (Uniaxial) Compressive Strength (UCS) Test, Advanced Terra Testing (ATT) (Golden, CO)