Kimberley Mineral Sands has confirmed their chief executive has been made redundant as Traditional Owners continue to raise concerns about alleged land clearing at one of the mining company's sites.

On Friday, Kimberley Mineral Sands' Chief Executive Officer Stuart Pether confirmed to National Indigenous Times that with KMS "having completed construction at Thunderbird and now moving into the operational phase", the Board has announced the Executive Team structure will be "simplified" over the coming months.

"Four Perth-based roles have been made redundant, including the role of KMS CEO," he said.

"The organisational change will support the Company's transition from a Perth-based development and construction business to a long-life West Kimberley-based operating project."

National Indigenous Times understands that Traditional Owner groups have raised concerns formally with the WA government regarding the Thunderbird project surrounding approvals for construction and land clearing, with particular regard to areas of heritage value.

One Traditional Owner and member of the Walalakoo Aboriginal Corporation told National Indigenous Times the company has allegedly cleared land without heritage surveys and without the appropriate environmental approvals.

Mr Pether told National Indigenous Times that KMS is "not aware of any unauthorised land clearing" and that the company "continues to engage with Traditional Owners under the Thunderbird Project Co-existence Agreement, which was executed in October 2018".

In September, Traditional Owners and other locals demonstrated at the Broome office of the company flagging concerns around the Thunderbird project's impact on heritage sites, the environment and local traffic.

Later that month it was revealed 15,000 litres of diesel leaked at Thunderbird's accommodation village after a pump malfunctioned.