strzał z odrobiną meritum ;)

całość:
fire gold assay with gravimetric finish
próba złota metodą ogniową z końcowym pomiarem grawimetrycznym/wagowym

Wydaje mi się, że chodzi o określenie jaką metodę (pomiaru, działania) stosuje się jako ostatni etap badania, przynajmniej w tym kontekście i na podstawie znalezionych w sieci przykładów.

http://www.agatlabs.com/minerals-and-metals/mining-geochemis...

Many techniques can be used for precious metal analysis and it is important to consider the sampling matrix when choosing the best methods for detection. Procedures for precious metal analysis include a combination of lead collection fire assay and either an ICP, ICP-MS, AAS and gravimetric finish.

http://www.answers.com/Q/What_is_gravimetric_finish

When assaying for metals, a gravimetric finish produces a small bead of the target metal (post fire assay), which is then weighed. This provides a way of confirming the fire assay figure.

http://www.srxassaylabs.com/assay/

It now only remains, to separate the silver from the gold. To do this, the bead is placed in a porcelain cup containing hot nitric acid on a hot plate. The nitric dissolves the silver leaving a small particle of pure gold. If the particle of gold is large enough, it is usually weighed to determine the original grade of the sample. This is called gravimetric finish to the fire assay.

http://www.alsglobal.com/~/media/Files/Divisions/Minerals/Ge...

SCREEN FIRE ASSAYS AND GRAVIMETRIC FINISHES
If a sample is identified to contain ‘coarse’ gold, a screen fire assay is the best way to obtain a definitive result. [...] If a client requires high accuracy for samples containing significant gold concentrations (>15 ppm), a gravimetric finish is recommended. Weighing a precious metal prill is inherently a more accurate procedure than the routine dissolution and spectrometric finish provided by most laboratories, mostly due to the reduced number of critical steps involved.

dodatkowe info w reference