I am glad to see the harmful environmental effects of sand mining getting more attention:
Here on the east coast of the USA, constant dredging of offshore sand to replenish beaches is harmful to the benthic communities just offshore.
One of many effects: falling populations of clams and other bivalves that sea ducks need for winter food. Repeated dredging (to forestall beach erosion) keeps "rebooting" invertebrate populations and with smaller and smaller windows between renourishment projects, the populations have less and less time to recover.
The dredging process also breaks up shells and countless tiny jagged shell pieces get mixed into the slurry that is pumped up onto the beach. This new sand mixture makes for a less hospitable beach for invertebrates that shorebirds depend upon.