Analytical figures posted anonymously on the Facebook page of the pro-transparency group Integrity Cambodia on Saturday estimates that if the UN data on sand exports to Singapore are accurate, Cambodia missed out on about $35 million in potential revenue.

The UN data show that since 2007, some $752 million in sand was imported by Singapore from Cambodia. The Kingdom has only reported about $5 million in exports to the small island nation during the same time period, prompting accusations of corruption and mismanagement in the much-maligned sector.

The $35 million estimate consists of $9 million in royalties, $15 million from tax on exports and about $11 million from tax on profits, the figures say. But the calculation uses several assumptions, including that the price of sand in Cambodia is one fifth of the price of sand in Singapore.

An anonymous contributor to the page characterised the numbers as a way to spark “critical thinking” on the potential for lost state revenue.

Meng Saktheara, spokesman with the Ministry of Mines and Energy, said the ministry had not been aware of the page, but said he had looked into the figures.

The calculation approach as presented “is rightly depicting Cambodia fiscal regime on this business”, he said. It’s a good way to “roughly estimate” potential state revenue, he added, while noting that the data wasn’t perfect.

“Based on my experiences and understanding of the global mining sector, the calculation on that page gives a good indication, although it has so many assumptions,” he said.

Meanwhile, the ministry on Saturday suspended the sand-dredging activities of Udom Seima Company around Koh Kong province’s Koh Smach island after it received a complaint that the company was operating too close to the riverbank, Dith Tina, secretary of state for the Ministry of Mines and Energy, confirmed.

Following the complaint, the ministry sent officials to check the area and found that the company’s operations were indeed too close to the riverbank, Tina said. “We ordered them to stop,” he said.

The ministry was waiting for a report from its provincial counterpart in Koh Kong to determine whether the company violated the provisions in its licence, he added. Tina also said the ministry had issued a letter to the company to suspend its export activity to review their contract information.

Sun Mala, an activist with the environmental NGO Mother Nature, said that on Thursday and Friday, activists with the organisation and a number of villagers observed Udom Seima was operating too close to a nearby mangrove forest, causing some parts to collapse.