A good sales contract will allow the seller and the buyer to attend the weighing, loading, discharging, sampling and sample preparation of their cargo. It is usually the case that a buyer will not have any qualified employees close to the loadport, and a seller will not have any qualified employees close to the discharge port. During the cargo handling, each respective party is typically represented by supervision companies who are engaged to ensure that proper and agreed procedures are maintained.
It is common in some jurisdictions for weight settlements to be made via draft survey weighing. Draft survey weights are determined by how low the vessel sits in the water, as measured against markings painted on the ships hull. Corrections are made for water temperature and salinity, vessel characteristics and flex in the hull. Done properly, a draft survey can give accurate weights.
On a mid-rangeHandysize vessel, a 1cm change in water level measurement on the hull is a 40MT variance in cargo weight. For a typical standard grade, low precious metals copper concentrate, this 1cm difference in measurement translates to more than $70,000 value.
Where draft surveys are not used, then weights are determined by either a belt weighing or a static weighing system. On well maintained, properly calibrated and correctly used shore scales, it is possible to achieve accurate weights.
Conrad Partners can provide inspectors who specialise in metal and mineral cargoes. We have extensive knowledge of local operations, from ports and warehouses to smelters and refineries. A Conrad Partners representative present during the discharging, weighing, sample collection and analysis of your products will add additional surety that your interests are well protected.
Our oversight services include:
- Supervision of weighing and sampling at loading, discharge and transit locations
- Sampling in accordance with international standards
- Draft surveys
- Packing and stowage inspections
- Stockpile surveys
- Warehouse inspection
- Sample preparation
- Moisture determination