Cerro rico is mined to this day, although there is not much silver left. Tin and lead, along with asbestos and arsenic, are present in the rock. Locals participate in cooperatives to mine these metals, hoping to one day strike a vein of silver and get rich. It is deadly work. The mines are essentially run the same way they were hundreds of years ago. Ore is hoisted up to exit tunnels and the mine trucks are pulled out by winch. There is no electricity or ventilation. The air inside is thick with dust and humidity, and the farther in you go the worse it is. The only support or safety structures are some wood beams wedged into place by hand. Inside the mountain is a tangled maze of tunnels, and there are over 400 entrances. Collapses are common and the entire top of the mountain once caved in. Moving from one level to another means crawling down steeply sloping tunnels on hands and knees or using crude ladders and ropes.