Analysing transportable moisture limits in Real Time

Manually analysing precise transportable moisture limits (TML) in ore stocks can be a time-consuming and fiddly process. With its elemental analysers, Real Time Instruments is complementing laboratory results with accurate, live analysis.

Completely eliminating water in the shipment of commodities like iron ore and coal is impossible.

Having the ability to analyse exactly how much moisture is in the ore prior to shipping will, however, help mines to add the most value to their exports and improves safety.

Real Time Instruments has been working alongside loading ports across Australia to develop moisture analysers to tighten the accuracy surrounding the results.

As Real Time Instruments chief sales officer Will Robinson explains, this increased accuracy allows for accurate communication of expectations between mining operations and their customers of the expected TML in the products they are shipping.

“First and foremost, when you’re purchasing any product, be it coal or iron ore, you don’t want to be paying for water,” Robinson tells Australian Mining.

“As moisture is always present, a maximum limit will be set as part of the custody transfer of the material and customers are expecting a certain ore grade without the moisture limit exceeded”.

While eliminating all moisture content from a shipment isn’t achievable, Real Time Instruments’ analysers are helping mining operations and their customers to set the expectation of exactly how much moisture to expect within the shipment in their contracts.

This not only helps to manage expectations and adhere to contracts, but is also a safety benefit, as shipments exceeding TML can cause cargo liquefaction and have disastrous consequences.

“If there is water in the ore it can accumulate on one side of the vessel as the ship rolls and pitches in the ocean,” Robinson explains.

“It doesn’t freely move through the ore like water would in a tank, particularly with coal and iron ore and at worst, this can cause ships to roll and capsize.

“If a ship does roll over there are millions of dollars tied to losing the ship and losing to cargo, so it is essential to have accurate analysers to get accurate TML measurements.”

Traditionally, TML has been determined manually in a laboratory, taking samples from the ore stockpile.

For large ore piles, this method is extremely difficult to calculate an accurate estimate, regardless of how many samples are collected.

“If you have a massive stockpile of say 100,000 tonnes, no matter how many samples the laboratory team grabs they will never get a perfect representation of that 100,000 tonnes as the moisture will vary throughout,” Robinson says.

“The results can take anywhere from six to 12 hours and sometimes days to analyse depending on how busy the laboratory is, and during that time if it sits on the stockpile it could rain or the moisture could drain out.

“Using Real Time Instruments’ elemental analyser, the ore is analysed as it flows on the conveyor belt on its way to port, so our analyser sees 100 per cent of the material processed, giving a truer average.”

While this is a continuous form of measurement compared to manual laboratory testing, Real Time Instruments’ analysers do not replace the need for laboratory workers.

The human workers are still a requirement to have the traceable standards and calibration of a laboratory when investigating TML.

As Robinson explains, Real Time Instruments’ analysers complement the existing work of laboratories, making their job easier without making the human role in detecting TML redundant.

“In the Pilbara, for example, five mines send samples to a single laboratory and due to the workload, results took approximately 12 hours to turn around, which severely impeded on operational decision making.

“Once the analysers were introduced, they were able to do the bulk of the work to take pressure off the laboratory. In addition, it provides another point of reference supporting the lab data in the event that a dispute arises between the mine and their customer.”

In addition to offering a more accurate TML reading, Real Time Instruments’ analysers can be used for selective processing, identifying higher or poorer grades of ore, to determine whether the ore has the quality to send straight to the stockpile or whether it needs to be cleaned or combined with higher ore grades.

This saves millions of dollars in water, electricity and retention time every year from the processing stage of the bulk handling procedure.

Real Time Instruments’ analysers are also used to gather and save data which is sent to the mining control system or uploaded to the cloud for later access.

“Our machine can measure up to 78 elements of the periodic table within the ore characteristic,” Robinson explains.

“This gets translated to an electronic format and sent to the mine control system or uploaded to the cloud where it is backed up and stored for months, enabling operators to go through the records to see the grade of ore and content of other elements from specific production regimes.

“Moreover, the data is used by the industrial control system (PLC/DCS) where better control decisions can be made in real time as the ore grade varies and it has its own histogram that stores data for the long term.”

Real Time Instruments has ambitious aspirations for the future of its analysers, as it is working to develop a neutron generator with a longer life span than existing options on the market.

“Neutron generators are an extremely expensive piece of equipment and existing technology only has a life span of about one year or so when being run at a 24/7 operating mine,” Robinson says.

“Our unit is in the final stages of commercialisation and has been tested and designed for a lifespan of 10-plus years.

“Having a piece of machinery that can run for 10 years without a worry is really exciting in this space and it will really open up our market in Europe too.”

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