Filmed in Romania, France and Spain. Despite the film's American setting, none of the footage was shot in the United States.
The types of chemicals used are not mentioned in the movie. Two different chemicals are used to mine gold - cyanide and sulfuric acid. Both are very dangerous and can cause chemical burns and death if ingested.
This movie was partially shot in Tabernas, Spain. Because of its similarities to North American deserts, it previously served as filming location for a large number of Western movies and series. Additional scenes were shot in Navarre and Aragon, Spain.
Despite receiving positive reviews from critics, this movie was a box-office failure, grossing just seven million dollars against its thirty-eight million dollar budget.