A woman who claimed she suffered brain damage as a baby due to lead poisoning caused by emissions from a mine in Mount Isa has lost a lawsuit against the mining company. 

Bethany Sanders, 17, represented by Slater and Gordon Lawyers and her guardian Jim Seeto, launched a civil case last year seeking $5 million in damages from Mount Isa Mines, owned by Glencore.

She claimed she had suffered severe developmental delays, lethargy and learning difficulties as a result of excess lead exposure from the mine as a baby.

Queensland Supreme Court Justice Frances Williams on Friday rejected the claim that the lead poisoning was the fault of the mine in her decision handed down in Brisbane.

"It is not contentious that the plaintiff's blood lead levels had substantially increased," Justice Williams said.

"What is contentious is the cause of this.

"Based on the evidence and findings ... the contribution of the ISA Caused Emissions to the overall level of dirt and dust that was in the plaintiff's environment was likely to be slight or minimal."

In a statement to ABC North West, a spokesperson for Slater and Gordon said the firm and the family were "disappointed and saddened by today's judgement, however we respect the decision of the court. We are considering the judgement".

Bethany Sanders was 13 months old when her family moved to Mount Isa in April 2007, and lived in the suburb Soldiers Hill, less than three kilometres from the mine.

Bethany's mother Sharnelle Seeto claimed that she knew nothing about the dangers of lead absorption in children and had not seen or heard any warning about the risk of children inhaling or ingesting dust or particle fallout from emissions.

At the time, Bethany was a crawling infant who would often play on the floor or in the yard, putting toys and her hands into her mouth.

She was also prone to eating dirt — a sign of the eating disorder known as pica, with which Bethany was later diagnosed.