Referring to a mining block, dilution happens in two different areas

𝟭-𝗜𝗻𝘁𝗲𝗿𝗻𝗮𝗹 𝗱𝗶𝗹𝘂𝘁𝗶𝗼𝗻. Sometimes within a mining block there are waste inclusions or low grade pockets of ore that cannot be separated and are inevitably mined with the mining block. This is called internal dilution. Internal dilution is difficult if not impossible to avoid. The amount of internal dilution varies in different types of deposits. Lithology and grade distribution are important factors in internal dilution. 𝟮- 𝗘𝘅𝘁𝗲𝗿𝗻𝗮𝗹 𝗱𝗶𝗹𝘂𝘁𝗶𝗼𝗻 External dilution also called contact dilution refers to the waste outside of the ore body that is mined within the mining block. External dilution varies based on geology, shape of ore body, drilling and blasting techniques, scale of operation and equipment size. This is the type of dilution that can be controlled using proper equipment and mining practices. Figure shows a mining block in a bench of an open pit mine with different types of dilutions.