Good Delivery Rules
Annex C: Weight Lists
This Annex shows the form of weight lists that should accompany shipments of Bars to Vaults. The form of listing used for Bars which are being submitted as part of an application for GD accreditation differs from that used for commercial shipments as shown below.
Weight lists accompanying Bars (whether for commercial shipments or for Bars submitted by applicants) must be provided in a machine-readable electronic form, such as an Excel or .csv file.
It is important that weight lists show the correct number of decimal places for the weights and assays.
1. Commercial Weight Lists
|Serial number||Brand code||Gross weight (troy ounces)||Assay||Fine weight (troy ounces)|
|Serial number||Brand code||Gross weight (troy ounces)||Assay|
Notes applying to both gold and silver:
- In cases where the Refiner weighs in kilograms, the weight list must show how the troy ounce equivalents are calculated using the method of conversion to gross and fine troy ounces shown overleaf. This uses the standard LBMA conversion factor of: 1 troy ounce = 0.0311034768 kg.
- In the case of commercial shipments of silver Bars, the fineness marked on the Bar and shown on the weight list should be in the same format (for example, whether 999.0,999 or 999.9).
If the weight is measured in troy ounces, it is not necessary to show the kilogram equivalent. The spreadsheet for making these conversions can be found in the GD Section of the LBMA website.
2. Vault Weights versus Refiner Weights
The algorithms shown on the following pages show how to convert metric to troy ounce weights and also how a troy ounce dead-weight should be converted to a final London weight. However, in cases where the Refiner’s weight differs from that determined by the Vault, the latter will be used for recording the troy ounce weight of the Bar.
Annex C (continued) – Sample Weight Lists and Conversions to Troy Ounces
The following tables show how to calculate the gross troy ounce (GTO) weight based on a metric weight and in the case of gold, also the rounded fine troy ounce (FTO).
The table below also shows how to convert an electronic troy ounce deadweight (e.g. in column (3)) to London GTO and FTO weights.
Bar No.1 - The initial conversion is truncated to 399.826 so deducting 0.002 gives a value of 399.824 in col (4) so the Bar is marked down to 399.800
Bar No.2 - The figure in col(9) is not rounded up to 398.345 as the rounding factor <900
Bar No.3 - The figure in col(9) is rounded up to 398.096 because the rounding factor is >900
- If the weight is initially measured in troy ounces, it is not necessary to show columns (1) and (2). A deadweight in troy ounces to three decimal places could be placed in column (3).
- When the original weight is measured in kilograms, the figure in column (2) is calculated by dividing the kilogram weight in column (1) by the conversion factor 1 troy ounce = 0.0311034768 kg.
- The figure in column (3) is derived from column (2) by truncating to the nearest 0.001 troy ounce.
- The figure in column (4) is derived by subtracting 0.002 troy ounces from the figure in column (3). See Annex C on weighing procedures.
- The figure in column (6) is derived by truncating the figure in column (5) down to the nearest 0.025 troy ounces.
- The figure in column (7) is derived by multiplying the figure in column (6) by 0.025. It is thus gives the London gross troy ounce (GTO) weight of the Bar.
- The unrounded fine weight in column (9) is calculated as the product of columns (7) and (8). The assay in column (8) must be shown to 4 decimal places.
- If the rounding factor shown in column (11) is 900 or more, the truncated fine weight – shown in column (10) - is increased by 0.001 to give the rounded fine troy ounce (FTO) weight in column (12). The factor in column (11) is derived from the 4th, 5th and 6th decimal digits of the figure in column (9).