An investigation into processing options for a complex, low grade uranium deposit has resulted in an unexpected new pathway for an Australian miner turned technology supply business. LOUIS WHITE reports
Article from resourceful: Issue 12
Mining complex or low grade ore often doesn't make economic sense using traditional processes.
The challenge of determining how to improve a process or develop an entirely new one to make a resource viable, often requires two or more parties coming together. Marenica Energy Limited (Marenica) approached CSIRO to better understand their calcrete-hosted carnotite deposit and investigate the best processing options.
"CSIRO applied their minds and equipment to understand the Marenica ore and establish solutions to specific mineral separations," Murray Hill, Marenica chief executive officer, says.
Characterisation to understand the issue
CSIRO's micro-characterisation team leader, Dr Peter Austin, says they have been working together since early 2012.
"The initial enquiry was for the characterisation of some ore samples, but it soon became apparent that the project would hinge on the combination of mineral characterisation and mineral processing expertise," Dr Austin says.
The Marenica orebody is extremely large, but relatively low grade. The cost of conventional processing would exceed the value of the ore based on the uranium prices of the day.
"I was not aware of the work that CSIRO did and the benefit they could bring to small companies like Marenica, and for that matter, the wider mining industry."
Problem-solving processing to lower costs
Marenica needed a low cost process to upgrade their ore to reduce capital and operating costs.
"Our mineral characterisation work identified key properties of the ore that we used to develop a new process," Dr Austin says.
"This process generates a significant upgrade of the uranium bearing mineral carnotite and removes other minerals that would otherwise create processing problems."
CSIRO then analysed the various steps utilising QEMSCAN and x-ray diffraction technologies to better understand how the ore behaved during processing. Marenica was able to use the mineralogical analysis to determine the most appropriate beneficiation techniques and optimise the process.
"When things didn't go as expected, they were also able to analyse the processed materials to understand the issues and make the required changes. This is not always the case with resource development," Dr Austin says.
As a result of the engagement with CSIRO, Marenica has developed its aptly named U-pgrade process. This process is the subject of several patent applications and Marenica are marketing the process as a solution for other uranium miners around the world. They are now a resource developer and a technology supply company.
"U-pgrade is a beneficiation process for upgrading secondary uranium ore by up to 50 times, halving capital and operating costs when compared to conventional processing," Mr Hill says.
"The process is applicable to secondary uranium ores that are located in semi-arid to arid environments around the world."
A pilot plant is now needed to further demonstrate the U-pgrade process. CSIRO's Waterford site in Perth has a process bay facility that is licensed for a substantial quantity of unsealed radioactive sources, suitable and purpose built for radioactive pilot plants.
"We are in the process of commissioning that facility as a registered radioisotope laboratory," Dr Austin says.
"By piloting the process, Marenica will be able to demonstrate its efficiency on a larger scale.
"If processing problems do occur, we have the tools to rapidly analyse samples and identify the root cause of the problems and assist Marenica to adjust the process to deal with them."