If the quarry is next to a road, footpath or somewhere else that people can easily get access to, then a properly maintained and effective barrier should be provided, otherwise the quarry will become a statutory nuisance as defined. (Section 151 of the Mines and Quarries Act 1954 & Environmental Protection Act 1990)
In Scotland the requirements under the Mines and Quarries Act 1954 are covered in the Statutory Nuisance Provisions of the Public Health etc (Scotland) Act 2008.
Please see Link to QR99 Reg 16 Guidance
Barriers should be inspected for trespass or damage at a frequency determined by experience. Inspections may need to be increased during periods of warm weather or school holidays
Where fences are damaged, take a photograph of the fence before and after repair to keep with the record of the inspection. If the damage is suspected to be the result of vandalism, it is good practice to report this to the police and get a crime number.
If Trespass is an issue then the Mineral Products Association offer resources for a ‘Stay Safe’ campaign that can be run with local schools and youth clubs.