Statistical Methods For Mineral Engineers (2024)

Conclusion: You cannot accurately sample coarse material with small masses. This explains why "scoop sampling" of conveyors is fundamentally flawed without proper mass reduction protocols (riffle splitters, rotary dividers). Once the mine feeds the plant, the mineral engineer shifts from geology to metallurgy. Here, Statistical Process Control (SPC) is the standard. The Moving Range Chart Most mineral processes have autocorrelation (tonnage now depends on tonnage 5 minutes ago). Traditional X-bar-R charts are less useful; Exponentially Weighted Moving Average (EWMA) charts are superior because they detect small, persistent shifts. Design of Experiments (DOE) Classical "one factor at a time" (OFAT) testing is statistically inefficient. Mineral engineers often face interactions (e.g., pH and collector dosage interact to affect recovery).

A allows the engineer to estimate main effects and interactions with minimal tests. Statistical Methods For Mineral Engineers

If $X$ is the vector of measured variables and $V$ is the variance-covariance matrix of measurements, we find the adjusted values $\hat{X}$ that minimize: Here, Statistical Process Control (SPC) is the standard

Where $p$ is the probability of recovery (the metal reporting to concentrate). Many flotation recovery curves follow a sigmoidal shape. The Hill equation (borrowed from biochemistry) models recovery as a function of residence time: Design of Experiments (DOE) Classical "one factor at