Resources · Methods reference

Methods reference.

Detection limits, upper limits, and digestion and finish details for every analysis we offer. Detection limits are typical lower limits and are matrix-dependent; upper limits mark the top of the reported working range. Full method sheets are available on request.

Request full method sheets Methods & price book Accredited CALA scope, ISO/IEC 17025 — Au fire assay and Cu/Pb/Ni/Ag/Zn ore-grade digestion.

Fire Assay (Gold)

Lead-collection fusion that refines the whole sub-sample into a silver dore bead, dissolved and measured. Available with an atomic-absorption finish for routine gold, a gravimetric finish for high-grade gold, or an ICP finish that also reports platinum and palladium.

Digestion Lead fusion (fire assay); dore bead dissolved in aqua regia

Method	Finish & digestion	Detection limit	Upper limit	Units
Au 30g AA Accredited Gold, AA finish Sample: 30 g (reduced to 15 g or lower for high-sulphide samples that will not fuse cleanly) Accredited under CALA Method A1 (gold by fire assay, AAS finish).	FA-AAS Lead fusion; dore bead dissolved in aqua regia, AA finish	5 ppb	—	ppb
Au/Pt/Pd 30g ICP Gold / platinum / palladium, ICP finish Sample: 30 g ICP finish is outside the accredited scope. Pt and Pd reported alongside gold.	FA-ICP (ICP-OES) Lead fusion; dore bead dissolved, ICP finish	Au 3 ppb	Au 2,500 ppb	ppb
Au 30g GRAV Gold, gravimetric finish Sample: 30 g For high-grade gold. Gravimetric finish is outside the accredited scope.	FA-gravimetric Lead fusion; dore bead parted and weighed	—	—	g/t

Total Pulp Metallics (TPM)

Coarse-gold screening for nuggety samples. The pulp is screened at 150 mesh; the entire +150 mesh fraction is fire-assayed and a 30 g subsample of the -150 mesh fraction is fire-assayed, then a weight-averaged total gold value is reported.

Digestion Lead fusion (fire assay) of the +150 and -150 mesh fractions

Method	Finish & digestion	Detection limit	Upper limit	Units
Au TPM Gold, total pulp metallics Sample: Whole pulp screened; 30 g subsample of the -150 fraction Requires Metallic Sieve preparation. Fire-assay AA finish on each fraction.	FA-AAS on screened fractions + weighted average Lead fusion of +150 and -150 mesh fractions	5 ppb	—	ppb / g/t

ICP Multi-Element (ICP-34)

A multi-element scan reporting up to 34 elements from a single 200 mg subsample, totally dissolved in four acids and read by ICP-OES. The lab's highest-volume analysis; often bundled with a fire-assay gold determination.

Finish ICP-OES Digestion 4-acid total dissolution Sample 200 mg (0.200 g)

Element	Detection limit	Upper limit	Units
Ag	0.2	6.0	ppm
Al *	0.01	20.00	%
As *	5	1,000	ppm
Ba	5	10,000	ppm
Be	0.5	1,000	ppm
Bi	2	1,000	ppm
Ca *	0.01	20.00	%
Cd	0.5	1,000	ppm
Ce	2	5,000	ppm
Co	2	550	ppm
Cr *	5	10,000	ppm
Cu	5	10,000	ppm
Fe	0.01	10.00	%
In	2	1,000	ppm
K *	0.01	10.00	%
La *	1	5,000	ppm
Mg *	0.01	10.00	%
Mn	1	20,000	ppm
Mo	1	1,000	ppm
Na *	0.01	10.00	%
Ni	1	1,100	ppm
P	0.01	10.00	%
Pb	2	2,200	ppm
S	0.01	20.00	%
Sb	3	440	ppm
Se	10	1,000	ppm
Sn *	10	1,000	ppm
Sr	1	10,000	ppm
Ti	0.01	10.00	%
U	2	1,000	ppm
V	1	1,000	ppm
W *	10	1,000	ppm
Zn	5	2,200	ppm
Zr	1	5,000	ppm

Units are ppm unless the element row reads %. Elements marked * may have limited solubility by this digestion.

Au + ICP Package

A bundled package pairing a 30 g fire-assay gold determination with the ICP-34 multi-element scan, run from the same submission. Available with a gold-only or a gold / platinum / palladium fire assay.

Digestion Fire assay (gold) + 4-acid total dissolution (ICP-34)

Method	Finish & digestion	Detection limit	Upper limit	Units
Au 30g + ICP-34 Gold (fire assay) + ICP-34 Sample: 30 g (Au) + 200 mg (ICP) Gold determination follows the accredited fire-assay AA method; the bundled ICP scan is outside the accredited scope.	FA-AAS + ICP-OES Fire assay (Au) + 4-acid (ICP-34)	Au 5 ppb; ICP per element	—	ppb (Au) / ppm-% (ICP)
Au/Pt/Pd 30g + ICP-34 Gold / platinum / palladium (fire assay) + ICP-34 Sample: 30 g + 200 mg ICP finishes are outside the accredited scope.	FA-ICP + ICP-OES Fire assay (Au/Pt/Pd) + 4-acid (ICP-34)	Au 3-2,500 ppb; ICP per element	—	ppb / ppm-%

Ore Grade Assay (Multi-Acid Digestion)

A higher-dissolution assay for samples above the trace-geochem range. A 0.200-2.00 g subsample is digested in three acids and measured by atomic absorption, suitable from about 0.01% up to 50-60% metal content. For Cu, Pb, Ni, Ag and Zn this is the lab's CALA-accredited digestion assay.

Finish AAS Digestion 3-acid digestion, AAS finish Sample 0.200-2.00 g

Element	Detection limit	Upper limit	Units	Accredited
Cu	0.01	—	%	A3
Pb	0.01	—	%	A3
Ni	0.01	—	%	A3
Zn	0.01	—	%	A3
Ag	0.1	—	g/t	A3
Co	0.001	—	%	—
Fe	0.01	—	%	—
Sb	0.01	—	%	—

Units are % except silver (g/t). Suitable to ~50-60% metal content

Geochemistry Trace (Multi-Acid Digestion)

Single-element base-metal geochemistry using a partial four-acid digestion of a 0.5 g split with an atomic-absorption finish, each element measured individually. Additional elements are available on request.

Finish AAS Digestion Partial 4-acid digestion, AAS finish Sample 0.5 g

Element	Detection limit	Upper limit	Units
Cu	1	10,000	ppm
Pb	1	10,000	ppm
Ag	0.2	6.0	ppm
Zn	1	10,000	ppm

Units are ppm.

Geochemistry - Water / Solutions (AA Finish)

Dissolved-metal and pH analysis of water and solution samples by atomic absorption, priced per element.

Finish AAS Digestion None (direct aspiration of solution); pH by meter Sample Liquid sample

Element	Detection limit	Upper limit	Units
Cu	0.01	—	ppm
Fe	0.01	—	ppm
Pb	0.01	—	ppm
Zn	0.01	—	ppm
pH	—	—	measured by meter

Units are ppm; pH is unitless.

Lithium / Specialty Package

A four-element specialty scan for lithium and critical-mineral pathfinders. A 1.00 g subsample is digested in four acids and read by ICP-OES, reporting Li, Nb, Sn and Ta in one scan.

Finish ICP-OES Digestion 4-acid digestion, ICP-OES finish Sample 1.00 g

Element	Detection limit	Upper limit	Units
Li	<5	100,000	ppm
Nb	<5	1,000	ppm
Sn	<10	1,000	ppm
Ta	<5	1,000	ppm

Units are ppm.

Notes

Detection limits are typical lower limits and are matrix-dependent; over-range results are re-run at a higher dilution or by an ore-grade method.
Accreditation to ISO/IEC 17025 through CALA covers gold by fire assay (AAS finish) and Cu, Pb, Ni, Ag and Zn by acid digestion (AAS finish). ICP-OES, gravimetric and multi-element scans fall outside the accredited scope. Verify the current scope in the public CALA directory.
Additional trace-geochemistry elements are available on request. For full method sheets or a matrix-specific quote, contact the lab.