11. In the past century, the Ablach Valley became an important center for gravel mining . 12. These machines can be used to demonstrate traditional clay, sand and gravel mining techniques. 13. Other activities that harm salmon are gravel mining , dredging and road building, scientists say. 14. But sanctuary status at Stellwagen Bank currently brings little more than restrictions on sand and gravel mining . 15. As the area was depopulated for many years, bush logging and gravel mining continued with vigour. 16. The local economy is based on agriculture, small businesses, gravel mining and a regional landfill. 17. The town neighbors an area of gravel mines , so its geography is spackled with mining lakes. 18. ,the most heavily contaminated areas at Cornhusker are the burning grounds with buried and unexploded gravel mines . 19. This year he was unable to pass legislation to stop an expansion of gravel mining on Maury Island. 20. Desert Island, Lamoine is a bedroom community to Ellsworth and Bar Harbor with an active gravel mining industry.
