3 Proven Scenarios: How to Replace Cyanide with Low-Toxicity Leaching Agents (Thiosulfate, Thiourea & PANDA) 655 3 Proven Scenarios: How to Replace Cyanide with Low-Toxicity Leaching Agents (Thiosulfate, Thiourea & PANDA) Published: May 26, 2026 Author: FKN Technical Team Meta Description: Struggling with carbonaceous or high-arsenic ore? Discover how Thiosulfate, Thiourea & PANDA gold dressing agent solve cyanide limitations. Boost recovery & meet ESG goals. Introduction: The Urgent Need for Non-Toxic Alternatives In modern gold mining, sodium cyanide (NaCN) remains dominant but faces increasing scrutiny due to its high toxicity and strict transportation regulations. As global environmental standards tighten, the industry is urgently seeking low-toxicity gold leaching agents that are both safe and efficient. Recent advancements have validated three primary alternatives: Thiourea, Thiosulfate, and Ferricyanide-based agents (like PANDA gold dressing agent). These reagents, often formulated with urea and caustic soda, offer a safer profile without compromising recovery rates. Based on the latest industrial data, this guide explores the three key scenarios where these reagents outperform traditional cyanide. Scenario 1: Conquering Carbonaceous Ores with Thiosulfate If your ore contains carbonaceous matter, cyanide leaching often fails due to the "preg-robbing" effect—where dissolved gold is re-adsorbed by the carbon in the ore. This results in significant metal loss. Why Thiosulfate is the Superior Choice Thiosulfate (S₂O₃²⁻) forms a stable complex with gold (Au(S₂O₃)₂³⁻) that is not easily adsorbed by carbon. This process operates in an alkaline medium, preventing equipment corrosion and ensuring environmental safety. Catalytic Mechanism: The presence of copper and ammonia significantly accelerates the dissolution kinetics. Ammonia diffuses to the gold surface, weakening the passivation effect. Industrial Proof: The world's largest thiosulfate leaching plant at Barrick Gold processes 10,000 tons of ore per day. This operation has proven that for carbonaceous ores, thiosulfate is not only technically superior but also economically competitive, achieving a recovery rate of 92.7%. For more details, please visit https://www.golddressingagent.com/blog/Cyanide-free-leaching-agent.html #Cyanidefreegoldleaching #Thiosulfateleachingprocess #Howtoleachcarbonaceousgoldore #PANDAGoldDressingAgent #Nontoxicgoldextractionalternatives

I'm sharing a slide set that takes a practical look at open pit optimisation and scheduling solutions currently on the market. Over the years, I've compared three foundational threads that keep coming up in this space: - Lerchs-Grossman (LG) - Lane (cut-off grade strategy) - Johnson (DBS) I'm not claiming every product fits neatly into one bucket -- but these reference points helped me build a clearer mental model for comparing what different tools are actually doing. In the deck, I focus on: - what different products optimise (and what they don't) - how constraints are represented (mining, processing, blending, geotech, haulage, destinations) - where results depend on assumptions that are easy to miss If you're evaluating tools, implementing one, or trying to get better outcomes from what you already have, I hope it helps. Question for others working in mine planning: What's the biggest gap you've seen between an "optimal" schedule in software and one that survives operations?

Revenue Factor (RF) in open pit optimization is a multiplier applied to the base commodity price to simulate different economic conditions; For example, an RF of 1.0 uses the actual price, while values below or above represent lower or higher price scenarios. When optimization is run at multiple RF values, it generates a series of pit shells that increase in size as RF increases, because more material becomes economically mineable. These shells are called nested pits since each smaller pit lies entirely within the larger ones. Nested pits represent different economic outcomes, allowing Engineers to assess project sensitivity to price changes where large variations indicate higher risk and to identify stable, high-value zones. They are also used to design mining stages (pushbacks), enabling a phased approach that improves cash flow, reduces initial capital requirements, and supports efficient long-term mine planning.

This document is to explain how and techniques of wall control blasting in Mining - Open Pit Operations.

(Indian Underground Coal Mine – Continuous Miner | DGMS Conditions) 🇮🇳 Understanding the balance between maximum coal recovery and pillar stability is critical in underground mining operations. In this study, I worked on: ✔️ Development Extraction Calculation – 29% ✔️ Depillaring Recovery – Final Extraction ≈ 86% ✔️ Pillar Stress Analysis using Tributary Area Method ✔️ Pillar Strength using Obert-Duvall Formula ✔️ Factor of Safety Evaluation (DGMS requirement ≥ 1.6) 📌 Result: The calculated FOS = 0.52, indicating an unsafe design — highlighting the importance of scientific pillar sizing and geotechnical validation before depillaring. This numerical exercise reinforces how engineering calculations directly impact mine safety, productivity, and regulatory compliance. Safety is not assumed. Safety is calculated.

Fundamental Pit Geometry ▪ Pit: The large, terraced excavation created to extract ore from near-surface deposits. ▪ Bench: A horizontal step cut into the pit, formed during mining to provide stability and access. ▪ Berm: A safety strip or horizontal shelf left between benches to catch falling rocks and support stability. ▪ Batter: The sloping surface of a bench wall. ▪ Batter Angle: The angle of inclination of the bench wall, measured from the horizontal. ▪ Face: The active rock surface where drilling, blasting, and loading occur. ▪ Crest: The top edge of a bench or slope. ▪ Toe: The bottom point where the bench slope meets the horizontal floor. ▪ Inter-Ramp Angle (IRA): The angle formed by a stack of benches without considering the berms at every level. ▪ Overall Angle: The final stable slope angle from pit crest to pit bottom, accounting for all benches and berms. Mining Operations & Equipment ▪ Pit Stages: Sequential mining phases that advance the pit outward and downward in planned steps. ▪ Loading: The process of picking up blasted rock using machinery such as shovels, excavators, or loaders. ▪ Hauling: Transporting ore or waste rock from the pit to dumps, crushers, or stockpiles using haul trucks. ▪ Haul Road: Engineered roads designed within the pit for the safe movement of heavy machinery. ▪ Shovel / Excavator: Primary loading equipment used to dig and load blasted rock. ▪ Front-End Loader: A versatile machine used for loading, stockpiling, and short-distance material movement. ▪ Dump: A designated area where waste rock is deposited. ▪ ROM (Run of Mine): Material delivered directly from the mine to the processing plant without any pre-crushing. ▪ Drilling: The creation of blast holes for explosives. ▪ Blasting: Fragmentation of rock using explosives to allow efficient excavation.

Heap leaching is a process where crushed ore is stacked on a lined pad and irrigated with a chemical solution that dissolves valuable metals for recovery. The efficiency of the process depends heavily on how the solution flows through the ore, which is influenced by particle size, shape, porosity, fines content, wettability, and fluid viscosity. High porosity and the presence of fines increase liquid hold-up and residence time, while spherical particles can cause channeling, creating fast flow paths that reduce contact with the ore. More wettable particles help spread the solution evenly, and higher fluid viscosity slows flow, increasing retention time. For effective irrigation, drip systems are preferred because they provide precise, controlled delivery of solution, reducing evaporation and promoting uniform wetting. Emitter spacing and flow rates must be adjusted according to ore characteristics; beds with high porosity or mixed fines require closer spacing or lower flow rates to prevent preferential channels. Initial wetting should start at low flow to allow fines to settle and establish uniform capillary distribution, followed by steady operational flow. Agglomerating fines or using binders can help maintain predictable permeability and reduce uneven flow. Monitoring and controlling the process is essential. Moisture distribution, flow uniformity, and solution properties should be regularly measured. Filtration and anti-clogging measures prevent emitter blockages, and adjustments to pump pressure and flow can compensate for changes in fluid viscosity or composition. Optimized irrigation improves metal recovery, reduces reagent consumption, minimizes solution losses, and lowers environmental impact. Implementing pilot tests or lab-scale trials can help determine the best irrigation strategy for each heap, ensuring consistent and efficient leaching performance.

[PT] A tese propõe modelos para prever o TML (PFD80) exigido pela IMO, reduzindo tempo de resposta e volume de amostra em relação a ensaios tradicionais. Mostra que granulometria (p.ex., D60/D10) é o principal fator, enquanto mineralogia/química e hidratação modulam o TML por meio de porosidade e retenção de água. Os modelos dão suporte a decisões de embarque mais rápidas e seguras. É uma solução operacional que melhora compliance e minimiza riscos logísticos. [EN] The PhD proposes models to predict the TML (PFD80) mandated by the IMO, cutting turnaround time and sample requirements versus standard tests. It shows particle-size distribution (e.g., D60/D10) as the key driver, while mineralogy/chemistry and hydration affect TML via porosity and water retention. The models enable faster, safer shipment decisions. It’s an operational solution that strengthens compliance and mitigates logistics risk.

Les minerais métalliques sont enfouis sous une couche de sol ordinaire ou de roches (appelée ‘morts terrains’ ou ‘déchets de roche’) qui doit être déplacée ou creusée pour permettre l’accès au dépôt de minerai métallique. L’accès au gisement est assuré par le creusement des tranchées ou inclinées pouvant être soit extérieures, soit intérieures. Les Rampes d’Accès ou encore appelés les Tranchées d’Accès sont les premiers maillons de la conception des fosses d’exploitation minière. Une bonne conception des voies d’accès diminue les pertes de rendement et permet également une optimisation de la production manière. Les ondulements des routes affectent également négativement la durée de vie des pneus, la consommation de carburant, la durée de vie du châssis du camion, la perte de production, etc.

Les sociétés minières qui réussissent gèrent leur planification minière comme un processus intégré et hiérarchique. Les niveaux hiérarchiques sont basés sur l'horizon de planification, allant de la planification à long terme à la planification à court terme. Le plan à long terme définit l'orientation stratégique globale et se concentre sur la réalisation des objectifs de l'entreprise à long terme. Les plans à long terme abordent essentiellement la question « Où » : où voulons-nous nous voir en tant que mine/organisation à l'avenir ? Les plans à plus court terme fournissent progressivement plus de détails et de précision dans une quête pour répondre à la question « Comment » : comment pouvons-nous atteindre au mieux le « où » qui est défini à long terme. En termes simples, les plans à court terme définissent les tactiques d'extraction et allouent les ressources (humaines et matérielles) afin de réaliser le plan à long terme.