Roraima Gold

A well-established American professor of Geology is asked by the State Department to investigate goings on at an american owned gold mine in the interior of the small South American nation of Guyana. The mine is located on the border with Brazil and near the Guyana town of Lethem in the foothills of the Roraima plateau. There are a number of unusual sicknesses leading to death in the native Amerindian villages near the mine. Luke is met at the mine by hostility on the part of the American manager and his staff, and Luke is able to determine that he is being withheld access to parts of the mine. A Brazilian doctor, Maria Alves, has been directed by her government to investigate the sickness among Brazilian workers at the mine. She and Luke work as a team to solve the mystery. A hit man has been hired to kill Luke and he only escapes with his life through the good graces of a Catholic nun he meets in Lethem. Luke is helped in his exploits by a fellow American geologist, now living in Guyana, who was the subject of an earlier novel by the author, "The Dark Stone".