How to select milling and crushing equipment.

To the average eye, there appears to be little difference between the numerous rocks and ores around Northern Ontario, but when it comes to choosing the right milling and crushing equipment, all rocks are not created equal.

The types of rocks you are working with will have an impact on the type of equipment you need to get the job done.

Before buying equipment you need to take a long look at your rocks or ores and ask the following questions:

    How hard is the material?
    How abrasive is the stone?
    How compressed is the material?
    What size is the material you are crushing?

Before selecting any machinery, you need to find out if you are working with a hard and abrasive substance, like copper ores, or a softer stone, like a limestone-type material.

While limestone can be crushed by the same machine that is capable of crushing harder ores, it may be difficult for your crusher to deal with tougher material if it is designed for softer substances.

You need to ensure the crusher will be used so it reflects the type of material you are crushing. To do this, you should learn if you need a single or double toggle crusher.

Even though the majority of single toggle crushers are well built, due to the motion of the machine they should be reserved for use with soft and nonabrasive materials. Hard rocks and ores, those with 18,000 to 20,000 PSI, are more economically crushed in double toggle crushers.

This is because the wear factor with a double toggle machine is less than with a single crusher, which will work harder to crush stronger material. The double toggle is robust enough to deal with hard ores, and because of this, the life span of the machine is significantly greater than with the single.

You should also give consideration to how many tonnes of rock a day you expect to crush in the machine, and whether there will be a secondary, or even a third step in the process before the rock reaches its final size.

A decision will also need to be made as to whether you plan to filter out smaller material before or after the crushing process. Prior to entering the crusher, finger-like accessories can be installed to separate the smaller pieces of stone to prevent it from being crushed along with the larger pieces.

If you don't have these fingers, you may need a larger crusher because more material will be going through the machine.

When you purchase you will also want to decide whether to buy a portable or stationary plant to work with. Portables are more useful if you are a contractor going site to site, compared to a stationary plant, which is heavy duty, and is better if ore and rocks are being brought to a single site.

You will also have the option of buying new or reconditioned machines. Dealing with a reputable reconditioning shop will ensure you are not getting what is known in the business as a "five-gallon refurbishing."

Companies that properly refurbish crushers will offer the same warranties as they do with new machines.

Look for a company that is reputable among mining companies, has been in business for a long time, and has a track record for supplying the spare parts which may be needed during the life of the machine.

If your mine is going to be in operation for 20 or 30 years, a new crusher becomes viable, however if you are only going to use a crusher for a few years, a reconditioned-to-new-specification crusher may be the better cost effective option.

While the length of time the machine will be used is an important determination of what you should buy, so too is your budget.

Both reconditioned and new crushers are built to the same specifications and dimensions, and one will not produce more tonnage then the other.