Stradbroke Island sand miner Sibelco back in court Sand mining on Stradbroke Island. Stradbroke Island sand miner Sibelco is back in court to deny trading white sand on the black market. Conservationists say the company's licence doesn't allow for extraction of white sand from the island east of Brisbane, but Sibelco says it has obtained the sand and sold it to landscaping companies legally. Today their dispute is back in Queensland's Supreme Court for the third time. Sibelco was named Unimin when in 2008 the Environmental Protection Authority raided its offices and found information it believed showed the miner was wrongly selling white sand - as opposed to mineral sand - to local landscaping and construction companies. In broad terms the higher-quality, white mineral sand - silicate sand - is used to make glass, while the lower quality sand is used for landscaping or for render in construction. Earlier this year a Queensland magistrate found the company had ""a case to answer"" on the charges put forward by the EPA under Queensland's Environmental Protection Act. Essentially the magistrates court ruled that Sibelco was a licensed mineral sand miner, but it did not have the necessary permits to sell the white sand to landscaping companies. Conservationists argue it has given the company a cash flow it is not licensed to have. Sibelco, however says it extracted the white sand - classed as a ""non-mineral"" sand - under the terms of its mineral sands extraction licence and has paid royalties to the state government. Sibelco has twice before appealed this matter through the Supreme Court and was eventually fined $255,000 in court costs for trying to delay the legal process. The company argues that the colour and quality of the sand is a complex factor of chemical properties of the sand where the original ruling erred. However on June 24, 2010, three Queensland Court of Appeal judges ruled otherwise and dismissed Sibelco's appeal. Sibelco returns to court on Wednesday to again appeal the findings. Last week Mines Minister Andrew Cripps said he was considering a proposal to extend the time allowed for sand mining on Stradbroke Island at Sibelco's Enterprise Mine from 2019 to 2035. The Friends of Stradbroke Island on Wednesday called for a public inquiry into the handling of the issue by the current and former state governments.