In 1984 the OK Tedi Mining Company Limited began mining copper and gold mineralization from Mt. Fubilan, which is located at the headwaters of the OK Tedi. Subsequent mining in the region followed in 1990. Since this time there has been intense monitoring of the environment undertaken by those in the field in order to better understand the possible impact of mining. This book assembles and summarizes research spanning two decades undertaken by leading experts with firsthand experience. Much of this research is contained in internal company reports, giving the reader rare insight and firsthand knowledge.