How do you design a sampling plan for a complex ore deposit?

2 Characterize the deposit

The next step is to characterize the deposit as much as possible, using existing information from geological maps, exploration drilling, geophysical surveys, mineralogical studies, and previous sampling campaigns. This will help you to identify the main features and zones of the deposit, such as lithology, alteration, mineralization, grade, and ore types. You will also need to assess the spatial variability and heterogeneity of the deposit, which will affect the sampling design and the sampling error. You can use statistical and geostatistical methods, such as variograms, kriging, and simulation, to quantify and model the spatial variability and heterogeneity of the deposit.

3 Select the sampling method

The third step is to select the sampling method that is most suitable for your objectives and deposit characteristics. There are different types of sampling methods, such as grab sampling, channel sampling, core sampling, reverse circulation sampling, and blast hole sampling, each with its own advantages and disadvantages. You will need to consider factors such as the sampling unit size and shape, the sampling frequency and density, the sampling depth and orientation, the sampling representativeness and bias, the sampling quality control and assurance, and the sampling logistics and safety.

4 Define the sampling protocol

The fourth step is to define the sampling protocol, which is the set of rules and procedures that you will follow to collect, handle, transport, prepare, and analyze the samples. The sampling protocol should ensure that the samples are representative of the population of interest, and that they are not contaminated, lost, or altered during the sampling process. You will need to specify details such as the sampling equipment and tools, the sampling location and marking, the sampling identification and labeling, the sampling preservation and storage, the sampling splitting and subsampling, and the sampling dispatch and delivery.

6 Evaluate the sampling results

The final step is to evaluate the sampling results, which is the data that you obtain from the analysis of the samples. You will need to check the data for errors, outliers, and anomalies, and apply any necessary corrections or adjustments. You will also need to interpret the data in relation to your objectives and deposit characteristics, and use appropriate methods to estimate and report the grade and tonnage of the deposit. You can use graphical and numerical methods, such as histograms, scatter plots, box plots, maps, cross-sections, profiles, tables, and statistics, to visualize and summarize the data. You can also use geostatistical methods, such as kriging, simulation, and block modeling, to interpolate and extrapolate the data.