At the Barrick gold mine at North Mara, Tanzania, a woman pours mercury into her palm. She mixes the mercury with water and rock fragments to seek gold from bits of waste rock at the Barrick mine. Hundreds of local men and women invade the mine every day, seeking pieces of waste rock that might contain gold. Barrick is investigating allegations that about 10 women who trespassed on the mine were sexually assaulted by about a dozen Barrick security guards and Tanzanian police.Geoffrey York