| The Variable Gravity (VG) package is supplied as standard equipment on all Knelson continuous concentrators (CVD) and as an option on all Knelson semi-continuous (batch) concentrators.
This package enables the concentrator to be operated over a broad range of rotational speeds which can assist to optimize recovery in the desired particle size range specific to the application.
The VG package consists of a variable frequency drive (VFD) coupled to the appropriately sized electric motor and integrated with the machine's automated control system.
The Variable Gravity package has successfully been applied in diamond indicator test work, regrind mill circuits, various flotation concentrate streams and tailings operations.
In order to confirm that the addition of a VG package can provide an economic benefit, basic laboratory testwork is recommended. In many instances, initial results may indicate a perceived metallurgical benefit however prior to making this determination, all economic factors must be considered.
These include:
- Increased power consumption
- Additional water usage
- Abrasion rates / unit wear and tear
- Additional capital cost
"It's quite remarkable when you consider that the Knelson units (equipped with VG packages) are achieving in excess of 70% recovery in a single pass of which over 83% of the values are in the -38 micron fraction," commented Ish Grewal, Manager of Knelson's Research & Technology Centre. - more on this.
Testwork of this nature can be conducted at the Knelson Research & Technology Centre (KRTC) or at your nearest G-Tec facility. | 
