AQUA REGIA “PARTIAL” DIGESTION

This leach uses a combination of concentrated hydrochloric and nitric acids to leach sulphides, some oxides and some silicates.

Mineral phases which are hardly (if at all) attacked include barite, zircon, monazite, sphene, chromite, gahnite, garnet, ilmenite, rutile and cassiterite. The balance of silicates and oxides are only slightly to moderately attacked, depending on the degree of alteration. Generally, but not always, most base metals and gold are usually dissolved.

0.5g of sample is digested with aqua regia for 2 hours at 95 °C. The sample is then cooled and diluted with deionized water. The samples are then analyzed using a Varian ICP for the 35 element suite. QC for the digestion is 15% for each batch, 2 method reagent blanks, 6 in-house controls, 8 sample duplicates and 5 certified reference materials. An additional 20% QC is performed as part of the instrumental analysis to ensure quality in the areas of instrumental drift.

Elements and Detection Limits (ppm)

Element Detection LimitUpper Limit
Ag0.2100
Al0.01%10%
As210,000
Ba1-
Be11,000
Bi10-
Ca0.01%10%
Cd0.52,000
Co110,000
Cr2-
Cu110,000

Element Detection LimitUpper Limit
Fe0.01%50%
K0.01%10%
Mg0.01%25%
Mn2100,000
Mo210,000
Na0.01%-
Ni110,000
P0.001%10
Pb25,000
S0.01%20%
Element Detection LimitUpper Limit
Sb10-
Sc110,000
Sn10-
Sr110,000
Ti0.01%20%
V11000
W10-
Y11000
Zn110,000
Zr1-

Notes: Extraction of of each element by Aqua Regia Digestion is dependent on mineralogy . Assays are recommended for values which exceed the upper limits.

0.5g of sample is digested with aqua regia for 2 hours at 95 °C. The sample is cooled and then diluted with deionized water. The samples are then analyzed using an Agilent 700 series ICP for the 38 element suite. QC for the digestion is 15% for each batch, 2 method reagent blanks, 6 in-house controls, 8 sample duplicates and 5 certified reference materials. An additional 20% QC is performed as part of the instrumental analysis to ensure quality in the areas of instrumental drift.

Elements and Detection Limits (ppm except where noted)

Element Detection LimitUpper Limit
Ag0.2100
Al0.01%8%
As210,000
B1010,000
Ba1010,000
Be0.51000
Bi210,000
Ca0.01%10%
Cd0.52,000
Co110,000
Cr110,000
Cu110,000
Fe0.01%30%
Element Detection LimitUpper Limit
Ga1010,000
Hg110,000
K0.01%10%
La1010,000
Mg0.01%25%
Mn5100,000
Mo110,000
Na0.001%10%
Ni110,000
P0.001%5%
Pb25,000
S+0.01%20%
Sb210,000
Element Detection LimitUpper Limit
Sc110,000
  Sr110,000
 Te1500
Th2010,000
Ti0.01%10%
TlTl10,000
U1010,000
V110,000
W10200
Y11000
Zn210,000
Zr110,000

Notes: Extraction of each element by Aqua Regia Digestion is dependent on mineralogy.
+ Sulphide sulphur and soluble sulphates are extracted.

Assays are recommended for values which exceed the upper limits.

A 0.5g sample is digested in aqua regia at 90 °C in a microprocessor-controlled digestion block for 2 hours. Digested samples are diluted and analyzed by Perkin Elmer Sciex ELAN 6000, 6100 or 9000 ICP/MS. One blank is run for every 68 samples. An in-house control sample is run every 33 samples. Digested standards are run every 68 samples. After every 15 samples, a digestion duplicate is analyzed. Instrument is recalibrated every 68 samples.

Elements and Detection Limits (ppm, except where noted)

Element Detection LimitUpper Limit
Ag0.1100
Al0.01%8%
As0.510,000
Au0.5 ppb1,000 ppb
B202,000
Ba110,000
Bi0.12,000
Ca0.01%25%
Cd0.12,000
Co0.15,000
Cr110,000
Cu0.210,000
Element Detection LimitUpper Limit
Fe0.01 %30 %
Ga11,000
Hg0.0150
K0.01%5%
La110,000
Mg0.01%10%
Mn110,000
Mo0.110,000
Na0.001%5%
Ni0.110,000
P0.001%5%
Pb0.15,000
Element Detection LimitUpper Limit
S+1%20%
Sb0.1500
Sc0.110,000
Se0.510,000
Sr15,000
Te0.2500
Th0.1200
Ti0.01%10%
Tl0.1500
V21,000
W0.1200
Zn15,000

Note: Assays are recommended for values which exceed the upper limits.

Au is semi-quantitative due to the small sample size.

Extraction of each element by Aqua Regia Digestion is dependent on mineralogy.

+ Sulphide sulphur and soluble sulphates are extracted.

A 0.5g sample is digested in aqua regia at 90 °C in a microprocessor controlled digestion block for 2 hours. Digested samples are diluted and analyzed by Perkin Elmer Sciex ELAN 6000, 6100 or 9000 ICP/MS. One blank is run for every 68 samples. An in-house control is run every 33 samples. Digested standards are run every 68 samples. After every 15 samples, a digestion duplicate is analyzed. Instrument is recalibrated every 68 samples.

Elements and Detection Limits (ppm)

Element Detection LimitUpper Limit
Ag0.002100
Al0.01%8%
As0.110,000
Au0.5 ppb10,000 ppb
B15,000
Ba0.56,000
Be0.11,000
Bi0.022,000
Ca0.01%25%
Cd0.1-
Co0.15,000
Cr110,000
Cs0.02500
Cu0.210,000
Dy0.11000
Er0.11000
Eu0.1100
Fe0.01%30%
Ga0.02500
Gd0.11000
Element Detection LimitUpper Limit
Ge0.1500
Hf0.1500
Hg1010,000 ppb
Ho0.11000
In0.02500
K0.01%5%
La0.510,000
Li0.110,000
Lu0.1100
Mg0.01%10%
Mn110,000
Mo0.0110,000
Na0.001%5%
Nb0.1500
Nd0.025000
Ni0.110,000
P0.001%5%
Pb0.15,000
Pr0.11000
Rb0.1500
Re0.001100
Element Detection LimitUpper Limit
S­+1%20%
Sb0.02500
Sc0.110,000
Se0.110,000
Sm0.1100
Sn0.05200
Sr0.55,000
Ta0.0550
Tb0.1100
Te0.02500
Th0.1200
Ti0.001%10%
Tl0.02500
Tm0.11,000
U0.110,000
V11,000
W0.1200
Y0.01500
Yb0.1200
Zn0.15,000
Zr0.15,000

Notes: Au is semi-quantitative due to the small sample size. Extraction of each element by Aqua Regia Digestion is dependent on mineralogy. Unaltered silicates and resistate minerals may not be dissolved.

+ Sulphide sulphur and soluble sulphides are extracted.

A 0.5g sample is digested in aqua regia at 90 °C in a microprocessor controlled digestion block for 2 hours. The solution is diluted and analyzed by ICP/MS using a Perkin Elmer SCIEX ELAN 6000, 6100 or 9000 ICP/MS. One blank is run for every 68 samples. An in-house control is run every 33 samples. Digested standards are run every 68 samples. After every 15 samples, a digestion duplicate is analyzed. Instrument is recalibrated every 68 samples.

Certain elements (Ti, P and S) are analyzed by ICP/OES using a Varian 735 ES. This extends the dynamic range for a number of elements as well. International certified reference materials USGS GXR-1, GXR-2, GXR-4 and GXR-6 are analyzed at the beginning and end of each batch of samples. Internal control standards are analyzed every 10 samples and a duplicate is run for every 10 samples. This digestion is not total and will not dissolve silicates some oxides and resistate minerals (e.g., zircon, monazite, sphene, etc.).

Element Detection LimitUpper LimitReported By
Ag0.002100ICP/MS
Al0.01%8%ICP/MS
As0.110,000ICP/MS
Au0.5 ppb10,000 ppbICP/MS
B15,000ICP/MS
Ba0.56,000ICP/MS
Be0.11,000ICP/MS
Bi0.022,000ICP/MS
Ca0.01%25%ICP/MS
Cd0.011,000ICP/MS
Ce0.0110,000ICP/MS
Co0.15,000ICP/MS
Cr110,000ICP/MS
Cs0.02500ICP/MS
Cu0.210,000ICP/MS
Dy0.11,000ICP/MS
Er0.1-ICP/MS
Eu0.1-ICP/MS
Fe0.01%30%ICP/MS
Ga0.02500ICP/MS
Ge0.1500ICP/MS
Gd0.11,000ICP/MS
Hf0.1500ICP/MS
Hg1010,000 ppbICP/MS
Ho0.11,000ICP/MS
In0.02500ICP/MS
K0.01%5%ICP/MS
La0.51,000ICP/MS
Li0.110,000ICP/MS
Lu0.1%100ICP/MS
Mg0.01%10%ICP/MS
Mn110,000ICP/MS
Element Detection LimitUpper LimitReported By
Mo0.0110,000ICP/MS
Na0.001%5%ICP/MS
Nb0.1500ICP/MS
Nd0.025,000ICP/MS
Ni0.110,000ICP/MS
P0.001%5%ICP
Pb0.15,000ICP/MS
Pr0.11,000ICP/MS
Rb0.1500ICP/MS
Re0.001100ICP/MS
S0.001%20%ICP
Sb0.02500ICP/MS
Sc0.110,000IPC/MS
Se0.110,000ICP/MS
Sm0.1100ICP/MS
Sn0.05200ICP/MS
Sr0.55,000ICP/MS
Ta0.0550ICP/MS
Tb0.1100ICP/MS
Te0.02500ICP/MS
Th0.1200ICP/MS
Ti0.01%10%ICP
Tl0.02500ICP/MS
Tm0.11,000IPC/MS
U0.110,000ICP/MS
V11,000ICP/MS
W0.1200ICP/MS
Y0.01500ICP/MS
Yb0.1200ICP/MS
Zn0.15,000ICP/MS
Zr0.15,000ICP/MS

Notes: Au is semi-quantitative due to the small sample size.

Extraction of each element by Aqua Regia Digestion is dependent on mineralogy.

Unaltered silicates and resistate minerals may not be dissolved.

If any elements are over-range, an aqua regia assay can be performed

Assays provide quantitative determinations of elements in non-processed geological materials. Assays are usually required when samples are known or suspected to contain higher levels of metals.

A 0.5 g sample is digested in aqua regia and diluted volumetrically to 250 ml with 18 megaohm water. CANMET reference materials for the appropriate elements are digested the same way and are used as a verification standard(s). Samples are analyzed on a Varian Vista 735 ICP-OES or ICP-MS.

Code 8 – AR – ICP-OES Elements and Detection Limits

Element Detection Limit
Ag3 ppm
As 0.01 %
Cd

0.003 %

Co

0.003 %

Cu

0.001 %

Fe

0.003 %

Hg

0.001 %

Ni

0.003 %

Pb

0.003 %

Zn

0.001 %

Code 8 – AR – ICP-MS Elements and Detection Limits

Element Detection Limit
As

0.0004 - 1 %

Bi0.0001 - 1 %
Co0.0001 - 1 %
Cs0.0001 - 1 %
Cu0.0001 - 1 %
Ga0.0001 - 1 %
Ge0.0001 - 1 %
In0.0001- 1 %
Li0.0001 - 1 %
Mo0.0001 - 1 %
Ni0.0001 - 1 %
Pb0.0001 - 1 %
Re0.0001 - 1 %
Se0.0001 - 1 %
Sn0.0003 - 1 %
Te0.0001 - 1 %
Th0.0001 - 1 %
Tl0.0001 - 1 %
U0.0001 - 1 %
W0.0001 - 1 %
Zn0.0001 - 1 %

Note: Extraction for Aqua Regia is dependent on mineralogy.