Resource Estimation
Grade-Tonnage Curves: How to Read Them and When They Lie
A grade-tonnage curve looks simple — grade on one axis, tonnage on the other. But reading it correctly requires understanding what the curve assumes and what it hides.
Tutorial
Category: Tutorial
9 articles
Geostatistics
Kriging Neighborhood Analysis: Finding the Right Search Ellipse
Your kriging search ellipse determines which samples influence each block estimate. Too big and you over-smooth. Too small and you're noisy. Here's how to find the right one.
Geostatistics
Variogram Modeling: 5 Mistakes That Make Your Kriging Wrong
Your variogram is the foundation of your kriging estimate. Get it wrong and every block in your model is biased. Here are the five mistakes I see most often in Indonesian resource projects.
Drillhole
Drillhole Spacing for Exploration vs Infill: A Field Guide for Indonesian Deposits
How to set drill spacing for epithermal gold, porphyry Cu, laterite Ni, and sedimentary deposits in Indonesia. When infill drilling earns its cost — and when it's waste.
Geology
Geological Domaining: Splitting Your Deposit the Right Way
When to split domains, how to validate them, and the over-domaining trap. Indonesian epithermal case study showing why vein and halo must be estimated separately.
Geostatistics
Indicator Kriging for Cutoff Grade Decisions: When and How
When indicator kriging beats ordinary kriging, how to build probability maps from binary transforms, and threshold selection for Indonesian gold deposits.
QA-QC
Specific Gravity and Bulk Density: Why Your Tonnage Is Wrong
SG measurement methods, common errors, and why tonnage errors dwarf grade errors. Indonesian nickel laterite case study where SG varied 1.2 to 1.8 across the deposit.
Compositing
Compositing 101: How to Pick the Right Composite Length
Composite length is one of the most consequential and least-discussed decisions in resource estimation. Here's the field-tested framework for picking the right one.
Tutorial
Getting Started with Orebit GeoSuite — From CSV to First Chart in 5 Minutes
No account. No subscription. Free and open source. Open GeoSuite in your browser or install it as an offline app on Mac, Windows or Linux, load your CSVs, and you're working. Here's the 5-minute walkthrough.
From Orebit — practical geology tools for working geologists