You get two kinds of jumpers. One kind break in during operational hours, stand in a prominent spot until they get noticed, then wait as the police/ambulances/managers arrive and spend the next few hours being talked down. The other group break in when the site is closed, get in through a concealed area, then do a running jump straight off the edge.
None of them are pleasant. The first you have to deal with the psychological torture of trying to talk someone down (the H&S manager had to do this once, it absolutely traumatised her. Especially when the guy came back a week later and jumped anyway). In the second, you don't find the body until
happy with the Dbal max results the next morning, and it's usually the poor innocent bloke opening up who does. From that height, when a body lands it doesn't break, it splatters. Apparently one guy had his intestines several feet away from his body. It's absolutely horrific, and we've had people quit their quarrying careers because they couldn't face going back and seeing the spot where they found the body.
Not much can be done sadly, you can't turn the perimeter into Fort Knox. Thankfully it's uncommon nowadays, because it's awful for everyone involved. Seriously guys, suicide is never the answer