The black mass (BM) material produced from battery shredding is substantially non-homogeneous. The metal composition can have variances as high as 18% from sample to sample. It is vital to obtain a representative composition of the bulk material before processingMaterials processing to ascertain the efficiency of leachingLeaching involved in hydrometallurgyHydrometallurgy and thus, the recoveryRecovery of critical metalsCritical metals in battery material. Current industry standard practice does not always account for the significant variation in BM. Often, an insufficient amount of mass is analyzed from too few locations, resulting in an inaccurate reported composition of the bulk material. This study explores the quantity and location of samples taken from bulk BM in supersacks and their associated concentrations through extensive statistical analysis. Strategic sampling and robust acid digestion techniques provide an accurate, representative composition of the bulk material, thus developing a new analysis method that reduces variances to ±5% with a 95% confidence level.