Article on Autogenous mills - I thought it was interesting. Perhaps the new changes and patent Mr. Snaper is doing with the mill technology will solve these issues. There is competition here, especially with the new crushers but if Snapers enhancements fix these issues the mill roll-out could be a very nice profit maker.
Monday, 25 August 2014
Where are SAG mills going?
In our recent conversation, Prof. Alban Lynch was very sceptical about where semi-autogenous grinding (SAG) mills have gone, and thinks they have taken us along the wrong track. He feels that they may be attractive in terms of high productivity, but says that "their energy efficiency is poor, and I feel that these immense machines are going to turn into very large ball mills". Developments in fine crushing machines may turn out to be viable alternatives to SAG mills.
Interesting, as in a recent article in Mining Magazine (July/August 2014, pp. 27), Kurt O'Bryan of Weir Minerals says that, although SAG mills have been around for over 40 years, the demand to process more ore in less time is a key factor in where comminution trends are heading. He says that "SAG mills have to be bigger to meet these demands. Some are up to 12.1-12.8 m in diameter in order to handle the higher tonnages, and the size of these mills makes them harder to install and operate efficiently".
He says that Weir is seeing a rise in demand for larger cone crushers that are matched with large high pressure grinding rolls (HPGRs) for customers who want to replace SAG mills in order to increase efficiency. Utilising cone crushers and HPGRs allows ore to be processed from 250mm to 50mm in cone crushers, then down to less than 6mm from HPGRs. O'Bryan also explains that "the interparticle comminution inherent in the HPGR process is uniquely efficient relative to other forms of comminution in crushing or milling".
So what do the operators think? Do you have problems with SAG mills, and how do you view their future? Is finer crushing a viable alternative? And no doubt the manufacturers will have something to say?
AI
