The term "ton assay" in the context of the United States typically refers to the assay ton, which is a unit of measurement used in the mining industry to express the amount of valuable material contained in a quantity of ore. This measurement is particularly common in the context of precious metals like gold and silver.
An assay ton is defined as 29.1667 grams (or approximately 1.04 ounces) of ore material. Miners and metallurgists use this unit to represent a standardized sample size for the purposes of analyzing the ore's composition and determining the percentage of valuable minerals or metals within it.
The use of the assay ton is essential in assessing the economic viability of mining operations and estimating the potential yield of valuable minerals from a given ore deposit. By analyzing a sample that is equivalent to one assay ton, miners and analysts can extrapolate the likely yield from a larger quantity of ore.
So, when you encounter the term "ton assay US," it generally refers to the assay ton used in the United States for mineral analysis and mining-related calculations.
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.