I modelled an electronic device in openLCA (applying the ecoinvent 3.8 database, ReCiPe 2016 midpoint category (H)). For copper, I obtained a negative impact for the midpoint category 'land use'. The negative contribution refers to the process 'treatment of sulfidic tailings, from cinnabar mine operation, tailings impoundment | sulfidic tailings, from cinnabar mine operation' (e.g. bac60434-94ad-319e-9f13-dd26d30e849e). Initially I thought the reason for the negative contribution is the share of copper that is reused or because of precious byproducts obtained from copper mining. However, this seems not to be the case. Could you please clarify why the treatment of sulfidic tailings results in negative impacts for the midpoint category 'land use'?
I attached a screenshot, all negative contributions originate from the treatment of sulfidic tailings. Thanks a lot!