1. Introduction

The chapter begins by highlighting the extensive global impact of mine drainage, affecting 117 countries and covering nearly 32,000 km². It discusses acid mine drainage (AMD), its causes, and the significant economic burden it imposes, with remediation costs in the U.S. alone estimated at $12.1 to $26.5 billion USD. The text delves into the microbial processes and chemical reactions that contribute to AMD, focusing on the role of acidophilic bacteria in oxidizing sulfide minerals. It also explores the formation of contaminated neutral drainage (CND) and near neutral mine drainage (NMD), and their impact on surrounding ecosystems. The chapter then presents various active and passive treatment methods for mine drainage, comparing their effectiveness, costs, and environmental impacts. It concludes with a recommendation chapter and an outlook on future research directions, making it a valuable resource for professionals seeking to understand and address the complex challenges of mine drainage.