Prior to mining, all rocks contained in a mineral deposit must be placed in one of several categories known as ore types. Each ore type describes a different way that the rock will behave in processing. The ore type determines which process stream a particular mined unit will be sent to, sets expectations for process engineers and metallurgists, and forms the basis for recovery predictions and production estimates. At first, ore types are assigned mainly by geologists based on visible geological criteria (dominant ore mineralogy, estimated grade, rock type, alteration type). As metallurgical tests are carried out and process data accumulate, the resulting criteria may be factored into the ore typing process, typically as assays and recoverable metal using the relevant process(es). Other variables may also be incorporated into ore typing at operations if they are particularly important, such as grindability, preg-robbing, gangue reagent consumption, and the presence of especially deleterious minerals such as talc or smectite. The mine operation department may also redefine ore types and/or process destinations based on economic criteria. A “best” ore type is designated that (in theory) best describes how the rock will behave in processing. Codes representing this ore type are entered into the drill hole database, then interpreted on cross sections and level plans, and finally added to the block model. Ore types are iteratively reexamined and adjusted over the life of a project. Major difficulties in effective ore typing are (1) lack of communication between geologists and metallurgists, (2) the imprecision inherent in imposing clean categories on messy natural systems without discrete divisions, (3) the need for ore types to provide useful information for a wide range of processes, (4) difficulties in scaling up laboratory test results to mine production, and (5) conflict among geological, metallurgical, and economic criteria for ore typing.

在开采之前，矿床中所含的所有岩石都必须归入称为矿石类型的几个类别之一。每种矿石类型都描述了岩石在加工过程中的不同表现方式。矿石类型决定了特定开采单元将被发送到哪个工艺流程，为工艺工程师和冶金学家设定了期望，并构成了回收率预测和产量估算的基础。首先，矿石类型主要由地质学家根据可见的地质标准（主要矿石矿物学、估计品位、岩石类型、蚀变类型）来分配。随着冶金测试的进行和过程数据的积累，得出的标准可能会被纳入矿石分类过程中，通常作为使用相关过程的化验和可回收金属。如果其他变量特别重要，也可以将其纳入操作中的矿石定型中，例如可磨性、预浸料、脉石试剂消耗以及特别有害的矿物（例如滑石粉或蒙脱石）的存在。矿山运营部门还可以根据经济标准重新定义矿石类型和/或加工目的地。“最佳”矿石类型被指定为（理论上）最能描述岩石在加工过程中的表现。代表这种矿石类型的代码被输入到钻孔数据库中，然后在横截面和平面上进行解释，最后添加到块模型中。在项目的整个生命周期中，矿石类型会被反复重新检查和调整。有效矿石分类的主要困难是（1）地质学家和冶金学家之间缺乏沟通，（2）在没有离散划分的情况下对杂乱的自然系统强加干净的类别所固有的不精确性，（3）矿石类型需要为矿石类型提供有用的信息工艺范围广泛，(4) 将实验室测试结果扩大到矿山生产的困难，以及 (5) 矿石分类的地质、冶金和经济标准之间的冲突。