Abstract: The sieve analysis and atomic Absorption methods were applied for 21collected samples around Atbara region - River Nile State- Sudan. Three types of grinder were used in this study they are (1) A grinder (2) B grinder and (3) mill size to given us the general trend of gold concentrate with preferable grain size in area of case study. The gold assay result for different grain size within same sample reflect direct relationship between gold concentrate and grain size which gold increasing with finer grain size. he grain size equal or less than 0.075mm is the preferable size to recovery most gold from original material, and there is a difference in types of mills and efficiency, For each mill grinding time for each sample varies from the mill to another and it is reliable Depending on the test rate of the sieves in the sieves and definitely affects the reading of the concentrations of samples and therefore control the rate of raw inside is known and the percentage of milling as well as all depends on the quality control of the mining plants and reduces errors. From this study we conclude the sieve analysis isgood method to evaluate quality of various grinders.Abstract: The sieve analysis and atomic Absorption methods were applied for 21collected samples around Atbara region - River Nile State- Sudan. Three types of grinder were used in this study they are (1) A grinder (2) B grinder and (3) mill size to given us the general trend of gold concentrate with preferable grain size in area of case study. The gold assay...Show More