Notes, tools, and projects for practicing engineers.
Process design, separation, heat transfer, and mining — worked through with the calculations attached.
Latest write-ups
Worked explanations and field notes, written so the ideas carry the page.
Inside the Regeneration Kiln: Zones, Stages, Clinker, and Carbon Life
Barren carbon comes out of the strip looking usable and still fails in the next adsorption tank. Organic foulants, calcium scale, over-temperature damage, and clinker tell…
Sep 23, 2026
5 min read
Thickening and the Water Loop: Trash Screens, Flocculant, and Tailings
The CIL can be chemically perfect and still receive the wrong feed. Dilute slurry shortens residence time; grit loads pumps and screens; uncaptured water leaves with tailings and…
Design the Leach Experiment: Bottle Rolls, Central Composites, and Response Surfaces
Twelve bottle-roll points scattered across dose and pH will still leave an argument about “the best condition.” A designed experiment answers a different question: which factors…
Cyanidation Chemistry: Elsner's Equation, Speciation, and the Stability Window
A free-cyanide reading of 300 ppm looks healthy — until the gold barely dissolves and HCN alarms start to trend. The number alone does not tell you which cyanide species the gold…
Cyanide Consumers: Sulfide, Copper, Iron, and What Steals Your Leach
Only a small fraction of the cyanide charged to a gold plant ever dissolves gold. The rest is consumed by other minerals, oxidised in the circuit, or destroyed during effluent…
Before the Leach: Comminution and Gravity Recovery in a Gold Plant
Leaching can only act on gold that is exposed. Everything upstream of the CIL tanks — crushing, grinding, classification, and the gravity circuit — decides how much gold surface…
Gold Recovery Alternatives: Comparing Cyanide with New Lime Sulphur YX500
A higher bottle-roll recovery is an interesting result, not a plant decision. An illustrative teaching case compares cyanide with New Lime Sulphur YX500 and reaches maximum…
Calculators that do the work
Focused engineering utilities for quick checks, reports, and everyday process calculations.
Unit converter
Convert common process-engineering quantities with clear, traceable units.
Cumulative PSD report
Turn sieve analysis data into a cumulative particle-size distribution report and chart.
Cumulative PSDGold processing calculator
Check CIL residence time, reagent rates, gold balances, bottle-roll recovery, elution cycles, and reagent economics with transparent equations.
Gold processingLeach DOE explorer
Explore central-composite leach designs, first-order response surfaces, residuals, and recovery economics from an illustrative teaching dataset.