The "ton assay" or "ton assay UK" typically refers to the assay ton, a unit of measurement used in the mining industry to express the amount of valuable material contained in a quantity of ore. This unit of measurement is used similarly in both the United States and the United Kingdom.
An assay ton is defined as 29.1667 grams (or approximately 1.04 ounces) of ore material. It is a standardized sample size used for analyzing the composition of ore and determining the percentage of valuable minerals or metals present within it.
Miners and metallurgists use assay tons to assess the quality and economic potential of ore deposits. By analyzing a sample equivalent to one assay ton, they can estimate the likely yield of valuable minerals from a larger quantity of ore.
So, "ton assay UK" refers to the assay ton measurement used in the United Kingdom, which is the same as the assay ton used in the United States and other mining contexts.
The kilogram (kg) is the base unit of mass in the International System of Units (SI). It is defined as the mass of the International Prototype of the Kilogram (IPK), a platinum-iridium cylinder kept at the International Bureau of Weights and Measures (BIPM) in France.
Until May 20, 2019, the kilogram was defined by the physical prototype, but as part of the redefinition of the SI units, the kilogram was redefined in terms of fundamental constants. Since that date, the kilogram is defined by fixing the numerical value of the Planck constant (h) to be exactly 6.62607015 x 10^-34 joule-seconds.
This redefinition ensures that the value of the kilogram is now based on a constant of nature rather than relying on a physical object that could potentially change over time. It allows for a more precise and stable definition of the kilogram and other SI units.