Check with both FLS and Sandvik. The difference is generally the throughput and the hardness. Jaw crushers are smaller machines. Both companies have books detailing the usage parameters. You should be able to complete your scoping study from that.

It is a capex and opex issue as well. You need to know the rough $ for scoping study. Gyratory is surely more expensive.

Putting a primary gyratory underground is probably not recommended. You will find two significant issues. The first is that moving the smallest part from that crusher underground will challenge the undertaking because of weight and size. The smallest part for the largest jaw crusher is practical and much easier.

The second issue is that primary gyratory are significantly more complex and sophisticated that the jaw, so putting that kind of equipment underground, will bring with it maintenance costs and problems that are not worth the benefits that this machine would bring.

My advice and I have been involved in installing a few machines underground, is to for the jaw crusher.

As to supplier, well think about going for those companies that have hundreds of these machines underground, because they really know what the conditions are like down there.

If the capacity you require falls within the capabilities of a jaw crusher then go for that option. Gyratory crushers come into their own when the feed size is largely uncontrolled and when direct tipping at high capacity is required. Typically in underground operations the crusher feed is not coarse and lumpy as in an open pit and is usually passed over a grizzly before crushing. It would take some special circumstances to justify the additional excavation required, additional equipment cost and more difficult maintenance.

The only additional comment I would make is that in certain instances where mine fragmentation is likely to be coarse, the larger feed openings found in gyros can be highly advantageous and will allow the system to run with less interruptions from rock breaking in the feed opening. Gyros can be broken down in size both horizontally (usual), but also vertically, so transport size can be addressed. Another option is that TKF do a jaw-gyro crusher. It is essentially a normal gyro, but with a modified top-shell. This allows for larger feed, but using the body of a smaller gyro.

You may also wish to consider the MMD type sizers as a primary size reduction option for underground. Much less head space required as they are a low profile machine and used often in underground situations because of the low profile.

GYRATORY CRUSHER

1.Height required will be too high.

2.Difficulty in removing spares and fixing in UG.

3.Discharge product in down line operation.

4.Removal of shift, lifting shaft in UG is a difficult task.

5.Feeding is also to be thought.

6.Storing and feeding UG big size boulders may be difficult.

You have suggested and excellent machine for underground. The MMD mineral sizer will be perfect if the abrasion index of the ore is suitable. Transmin and MMD can help you with that.

It is always a fascinating discussion. The move to sizers has certainly gained more attention with the move to deeper block caves. In such instances the size of excavation required for a large (tall) crusher is a major concern. Although large gyros are still being deployed u/g up to 60-89 type machines. Sizers are being assessed by several companies, but feed strength and abrasively are still a major problem. The Codelco work with MMD has been openly discussed and this remains the best case study for such applications. Anyway, I think I have digressed from the original question, so no more from me on this subject.

It depends on the type of ore and throughput. Jaw Crushers may not be suitable for slabby ore, have low capacity and require heavy foundation because of the flywheel but they are easy to maintain unlike Gyratory crushers which are difficult to dismantle and very tall machines for underground installations.

If you are looking for technical paper comparing various primary crushers, kindly refer to "Selection and Sizing of Primary Crushers by Ronald W. Utley, General Manager, Crushing Division, FFE Minerals, Bethlehem, PA, USA", published in "Mineral Processing Plant Design, Practice, and Control Proceedings, Volume 1 edited by Andrew L. Mular, Doug N. Halbe, Derek John Barratt."