Large-scale limestone quarrying is contentious. Most mineral extraction licences were issued by national government for 90 years in the 1950s and remain legally binding. The park authority has a policy of considering applications for new quarries and licence renewal in the park in terms of the local and national need for the mineral and how unique the source is, in conjunction with the effects on traffic, residents and the environment. Some licences have not been renewed; the RMC Aggregates quarry at Eldon Hill closed in 1999 and landscaped. Proposals from Stancliffe Stone Ltd to re-open dormant gritstone quarries at Stanton Moor in 1999 became a test case, hotly contested by ecological protesters and residents on the grounds that the development would threaten Bronze Age remains at the Nine Ladies Stone Circle, and damage the natural landscape. In 2007, negotiations took place to relocate the development to Dale View quarry in a less sensitive area.