Neither too wet nor too dry

Measuring microwaves to keep things just right

Biking to work on a gravel road has given me a new appreciation of moisture. If the road becomes too wet, I get coated with mud. Too dry, and I get coated with dust.

Either way, it’s a minor inconvenience. But for companies that handle coal, iron ore, and other minerals, managing moisture is serious business. If the ore becomes too dry, it releases dust that can threaten the health of miners and of people living in nearby communities. In fact, coal dust and iron-ore dust both contribute to a variety of respiratory diseases, including cancer.

The solution is simple: moisten the ore to keep the dust in check. But how much moisture? Add too little, and you haven't solved the problem. Add too much, and the ore:

sticks to container surfaces and becomes hard to handle

becomes heavier and thus more expensive to ship

can shift suddenly during shipment, with potentially disastrous

wastes water that, in many mining areas, is in scarce supply

Enter an Australian company called Intalysis Pty Ltd (now Thermo Scientific). They have developed QNX-based, low-frequency microwave (LFM) analyzers that continuously measure the moisture content of ore as it moves along conveyer belts. Using this information, a mining company can add just the right amount of moisture to keep its ore both safe and easy to handle.

The basic premise is simple: When microwaves hit moist materials, they slow down and weaken. By measuring this attentuation, the system can calculate the ore’s moisture content. There are, of course, challenges, such as ensuring accurate measurements when using fast, high-capacity conveyors.

To help address these issues, the designers of the LFM₃ analyzer chose the QNX Neutrino OS, which supports both the fast data-acquisition rates and high uptimes needed by this application.

For more information on the LFM₃, click here.