I did not realise at the time that the industry was the subject of legal action by Friends of the Earth. Their objections are outlined here; there are several news reports of the progress of their case, eg here and here; this is an account, from June 2017, of the appeal court case; here is the BBC report of the decision and this is FOE’s reaction, which includes this:
Yesterday the Northern Ireland Court of Appeal ruled that the Northern Ireland government acted unlawfully by not stopping dredging for sand at one of Europe’s most important wetlands.
The only legal option now open to the government is to stop the sand dredging.
Dredging has been taking place on a huge scale at Lough Neagh without planning permission and other authorisations.
Friends of the Earth brought the legal challenge over the Northern Ireland government’s failure to stop the extraction.
Up to 2 million tons of sand is suction dredged from the bed of the lough every year. This is the biggest unauthorised development in the history of Northern Ireland. Yet this vitally important wildlife site is supposed to be protected under local and international law. In fact there is no bigger unlawful mine anywhere in Europe in a Special Protection Area.
Lough Neagh is Europe’s biggest wild eel fishery […].
I suspect that the decision will increase the DUP’s enthusiasm for Brexit.