Large volumes of waste rock (WR) are generated in open-pit mines. WR is characterised by high anisotropy in its physical, chemical, mineralogical, and hydrogeological properties. WR is often deposited in unsaturated piles on the mine surface. Mineralogical investigations defined the diameter of physical locking of sulphides (DPLS) allowing the WR to be separated into two fractions: i) a reactive fine fraction (<2.4 mm), and ii) an inert coarse fraction (>2.4 mm). Environmental desulphurisation carried out on the reactive fine fraction decreased the risk of contamination caused by WR oxidation. The geochemical behaviour of three benign desulphurised lithologies (altered greywacke (AGR), carbonated greywacke (CGR) and carbonated porphyry (CPO)) and their corresponding fine fractions (<2.4 mm) were assessed using kinetic weathering cells (WCs). These tests confirmed the effectiveness of environmental desulphurisation to prevent acid mine drainage formation. In fact, geochemical analyses of the leachates from WCs showed that pH values ranged between 7.4 and 8.9. Moreover, instantaneous concentrations of iron and zinc were below 0.5 mg/L and 3 mg/L, respectively. Pyrite oxidation rates, which represent sample reactivity, were higher for head samples (3.01, 4.86, and 2.54 μmol/kg/day for AGR, CGR, and CPO lithologies, respectively) in comparison to the benign desulphurised materials (2.32, 2.4, and 2.25 μmol/kg/day for AGR, CGR, and CPO lithologies, respectively). Pyrite in the dismantled material was only partially liberated or almost encapsulated, making it mineralogically unavailable for oxidation. The benign desulphurised material with low initial sulphide content was potentially non-acid generating at the long-term scale. Upstream environmental desulphurisation has been confirmed as an effective strategy for WR management and valorisation.

露天矿产生大量废石（WR）。WR的物理，化学，矿物学和水文地质特性具有高度的各向异性。WR通常沉积在矿山表面的不饱和桩中。矿物学研究确定了硫化物（DPLS）的物理锁定直径，使WR可分为两个部分：i）反应性细颗粒部分（<2.4 mm），和ii）惰性粗颗粒部分（> 2.4 mm）。对反应性细馏分进行的环境脱硫降低了WR氧化引起的污染风险。三种良性脱硫岩性（改变的格里瓦克（AGR），碳酸的格里瓦克（CGR）和碳酸盐的斑岩（CPO））及其相应的细级分（<2）的地球化学行为。使用动力学风化池（WCs）评估4毫米）。这些测试证实了环境脱硫对防止酸性矿山排水形成的有效性。实际上，对WC中渗滤液的地球化学分析表明，pH值介于7.4和8.9之间。此外，铁和锌的瞬时浓度分别低于0.5 mg / L和3 mg / L。与良性脱硫材料相比，代表良性脱硫材料的头部样品的硫铁矿氧化速率更高（分别为AGR，CGR和CPO岩性的样品分别为3.01、4.86和2.54μmol/ kg /天）。 AGR，CGR和CPO岩性分别为2.25μmol/ kg /天）。拆除后的材料中的硫铁矿仅部分释放或几乎被封装，使其在矿物学上无法用于氧化。初始硫化物含量低的良性脱硫材料从长期来看可能不会产生酸。上游环境脱硫已被确认为WR管理和增值的有效策略。