Measuring Moisture in Bauxite with Microwaves

Mark McGuinness, Sean Bohun, Vincent Cregan, William Lee, Jeff Dewynne, Gary O'Keefe, Tuoi Vo

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


Moisture measurement in bauxite ore as it is being offloaded from a ship is a challenge that was brought to a European Study Group with Industry at the University of Limerick in 2017. A refinery asked the Study Group to confirm if it is possible to calculate the moisture content once every second, by passing microwaves through the ore as it is being offloaded at about 2 m/s. The microwaves experience a phase shift and signal attenuation, depending on the amount of moisture present. We review the theory of microwave transmission through a polarising medium, and we present and study the data produced by the microwave analyser. We explore the consequences of the method for measuring phase change, and the effects of noise on the phase shifts observed. We provide an algorithm for lifting the measured phase shifts from their restricted range to an unlimited range for the true phase shift. Concurrent measurements of ore height are central to the lifting algorithm. We note the effect of interference on the attenuation seen in data.
Original languageEnglish
Title of host publicationProceedings of the Forum "Math-for-Industry" 2019
Subtitle of host publicationMathematics for the Primary Industries and the Environment
EditorsRobert McKibbin, Graeme Wake, Osamu Saeki
PublisherSpringer Singapore
Number of pages52
ISBN (Electronic)9789811911545
ISBN (Print)9789811911538
Publication statusPublished - 11 Sep 2022
EventForum "Math-for-Industry" 2019: Mathematics for the Primary Industries and the Environment - Massey University, Auckland, New Zealand
Duration: 18 Nov 201921 Nov 2019

Publication series

NameMathematics for Industry
PublisherSpringer Singapore
ISSN (Print)2198-350X
ISSN (Electronic)2198-3518


ConferenceForum "Math-for-Industry" 2019
Country/TerritoryNew Zealand
Internet address


Dive into the research topics of 'Measuring Moisture in Bauxite with Microwaves'. Together they form a unique fingerprint.

Cite this