The Blending Made the Spec. The Blending Created the Dispute.
Quote from chief_editor on April 26, 2026, 5:35 amBlending different lots to meet a specification creates cargoes where the average meets the target but individual components may not.
The contract called for iron ore fines with Fe 62% minimum, SiO2 5% maximum, Al2O3 2.5% maximum. The supplier at Saldanha Bay had two stockpiles. Stockpile A: Fe 63.2%, SiO2 4.3%, Al2O3 2.1%. Stockpile B: Fe 60.8%, SiO2 5.8%, Al2O3 2.9%. Neither met the full specification alone — Stockpile B was below Fe minimum and above both SiO2 and Al2O3 maximums.
The supplier blended at approximately 60:40 ratio. The blended analysis showed Fe 62.2%, SiO2 4.9%, Al2O3 2.4%. On paper, the blend met the specification. The cargo was loaded. At discharge in Qingdao, the buyer's surveyor sampled each hold. Holds 1 and 2 showed Fe 63.0%, SiO2 4.5%. Holds 3 and 4 showed Fe 60.9%, SiO2 5.7%. The composite showed Fe 62.0%, SiO2 5.1%. The buyer rejected on the basis of SiO2 exceeding the 5% maximum.
Blending Creates an Average That May Not Exist in Any Part of the Cargo
The fundamental issue with blending is that a weighted average can meet a specification while the component parts do not. A blend of 63% Fe and 61% Fe material produces 62% Fe on average — but no part of the cargo is at 62%. Every sample will yield either higher or lower depending on which stockpile material happens to be at that location in the hold.
Blending at a bulk terminal is imprecise. Two stockpiles are fed onto the conveyor belt in the target ratio, but the ratio varies as stockpile geometry changes and operational adjustments are made. The ratio that produces 62.2% in the laboratory may produce 63.5% in the first 20,000 MT loaded and 60.5% in the last 15,000 MT.
The buyer experiences this unevenness directly. A hold at 60.9% Fe requires different furnace adjustments than a hold at 63.0% Fe. The buyer bought a specification, not a statistical average. The buyer's operational reality requires consistency.
The operational judgment for sellers is that the contract should specify whether quality determination is based on the composite of the entire cargo or on individual hold analyses. If composite, blending is contractually acceptable. If hold-by-hold, or if silent, blending creates exposure because individual holds may not meet the specification.
The Sampling Location Determines Which Inconsistency Is Measured
If the cargo is sampled from the loading belt — cross-stream cuts at regular intervals — the sample captures the full stream including blending variation. The composite reflects the true average.
If sampled hold by hold at discharge — common when the buyer controls inspection — each hold sample reflects whichever portion of the blend filled that hold. Different holds may show different qualities.
The dispute was settled through arbitration. The tribunal ruled that the specification applied to the composite, based on the contract's reference to a single quality certificate for the full shipment. The buyer's claim was dismissed. But arbitration cost approximately $95,000 and took 8 months. The trade margin was $350,000. The arbitration consumed 27% of the margin.
The traders who blend regularly specify three things in every contract: quality is determined by composite analysis, the sampling methodology is cross-belt during loading, and the quality certificate covers the full shipment as a single lot. These specifications align the framework with the blending practice and eliminate the ambiguity that creates disputes. The traders who blend without specifying the method are creating a cargo that meets spec on average and hoping the buyer evaluates it that way. That hope holds until a buyer with a different method and different commercial motivation decides hold-by-hold is the correct basis — and the contract does not say otherwise.
Keywords: cargo blending specification dispute physical commodity trade | commodity cargo blending quality risk, blending iron ore coal specification, lot blending quality dispute trade, cargo blending methodology physical trade
Words: 593 | Source: Industry pattern — documented across multiple sources | Created: 2026-04-08
Blending different lots to meet a specification creates cargoes where the average meets the target but individual components may not.
The contract called for iron ore fines with Fe 62% minimum, SiO2 5% maximum, Al2O3 2.5% maximum. The supplier at Saldanha Bay had two stockpiles. Stockpile A: Fe 63.2%, SiO2 4.3%, Al2O3 2.1%. Stockpile B: Fe 60.8%, SiO2 5.8%, Al2O3 2.9%. Neither met the full specification alone — Stockpile B was below Fe minimum and above both SiO2 and Al2O3 maximums.
The supplier blended at approximately 60:40 ratio. The blended analysis showed Fe 62.2%, SiO2 4.9%, Al2O3 2.4%. On paper, the blend met the specification. The cargo was loaded. At discharge in Qingdao, the buyer's surveyor sampled each hold. Holds 1 and 2 showed Fe 63.0%, SiO2 4.5%. Holds 3 and 4 showed Fe 60.9%, SiO2 5.7%. The composite showed Fe 62.0%, SiO2 5.1%. The buyer rejected on the basis of SiO2 exceeding the 5% maximum.
Blending Creates an Average That May Not Exist in Any Part of the Cargo
The fundamental issue with blending is that a weighted average can meet a specification while the component parts do not. A blend of 63% Fe and 61% Fe material produces 62% Fe on average — but no part of the cargo is at 62%. Every sample will yield either higher or lower depending on which stockpile material happens to be at that location in the hold.
Blending at a bulk terminal is imprecise. Two stockpiles are fed onto the conveyor belt in the target ratio, but the ratio varies as stockpile geometry changes and operational adjustments are made. The ratio that produces 62.2% in the laboratory may produce 63.5% in the first 20,000 MT loaded and 60.5% in the last 15,000 MT.
The buyer experiences this unevenness directly. A hold at 60.9% Fe requires different furnace adjustments than a hold at 63.0% Fe. The buyer bought a specification, not a statistical average. The buyer's operational reality requires consistency.
The operational judgment for sellers is that the contract should specify whether quality determination is based on the composite of the entire cargo or on individual hold analyses. If composite, blending is contractually acceptable. If hold-by-hold, or if silent, blending creates exposure because individual holds may not meet the specification.
The Sampling Location Determines Which Inconsistency Is Measured
If the cargo is sampled from the loading belt — cross-stream cuts at regular intervals — the sample captures the full stream including blending variation. The composite reflects the true average.
If sampled hold by hold at discharge — common when the buyer controls inspection — each hold sample reflects whichever portion of the blend filled that hold. Different holds may show different qualities.
The dispute was settled through arbitration. The tribunal ruled that the specification applied to the composite, based on the contract's reference to a single quality certificate for the full shipment. The buyer's claim was dismissed. But arbitration cost approximately $95,000 and took 8 months. The trade margin was $350,000. The arbitration consumed 27% of the margin.
The traders who blend regularly specify three things in every contract: quality is determined by composite analysis, the sampling methodology is cross-belt during loading, and the quality certificate covers the full shipment as a single lot. These specifications align the framework with the blending practice and eliminate the ambiguity that creates disputes. The traders who blend without specifying the method are creating a cargo that meets spec on average and hoping the buyer evaluates it that way. That hope holds until a buyer with a different method and different commercial motivation decides hold-by-hold is the correct basis — and the contract does not say otherwise.
Keywords: cargo blending specification dispute physical commodity trade | commodity cargo blending quality risk, blending iron ore coal specification, lot blending quality dispute trade, cargo blending methodology physical trade
Words: 593 | Source: Industry pattern — documented across multiple sources | Created: 2026-04-08