DS-1 is a gold ore from the Deep Star mine in Carlin Mine Complex, Nevada, USA which was donated by Newmont Mining Corporation.
The mineral species include: quartz (35.5%); feldspars (mainly K-feldspars and lower proportions of albite at 13.6%); dolomite (15.5%); mixed clays (7.5%); mica (mainly muscovite, lower proportions of biotite, trace phlogopite at 6.5%); ankerite (8.5%); pyrite (3.9%); kaolinite (2.8%); calcite (2.4%); pyrrhotite (1.3%); arsenopyrite (0.9%); jarosite (0.5%); garnet (0.3%); gypsum (0.1%); barite (0.2%); apatite, pyrophyllite, realgar, rutile and siderite at 0.1%; and magnetite, sphlerite and wollastonate at trace levels.
DS-1 is suitable for the analysis of gold and various other elements at major, minor and trace levels in gold ores. Examples of intended use include quality control and method development.
INSTRUCTIONS FOR USE
DS-1 should be used “as is”, without drying. The contents of the bottle should be thoroughly mixed before taking samples. The values herein pertain to the material when produced. CANMET-MMSL is not responsible for changes occurring after shipment.
Normal safety precautions for handling fine particulate matter are suggested, such as the use of safety glasses, breathing protection, gloves and a laboratory coat.
METHOD OF PREPARATION
The raw material was air dried and dried at 65°C for 48 hours, crushed, milled, sieved to remove the plus 74 µm fraction. The product was blended, and then bottled in 400-gram units. The recovery was 72%.
The homogeneity of the stock for arsenic, copper, gold and sulphur was investigated using twenty-two bottles chosen according to a stratified random sampling scheme. Two splits were analyzed from each bottle. The splits were analyzed for gold by lead fire assay followed by atomic absorption spectroscopy using a 30–gram sample. Arsenic was determined in 0.1 gram–samples using an aqua regia digest with a microwave followed by determination using inductively coupled plasma – optical emission spectroscopy. Samples of 0.25 grams were used to determine copper using a four-acid digestion and determination by inductively coupled plasma – mass spectrometry. Sulphur was determined on 0.1 gram samples by combustion and infrared detection.
Use of a smaller sub-sample than specified above for these elements will invalidate the use of the certified values and associated parameters. A one–way analysis of variance technique (ANOVA) was used to assess the homogeneity of these elements. For these four elements the mean squares of the between-bottles variation is similar to or, less than the within-bottle variation. Thus, no significant between-bottle variation was observed for arsenic, copper, gold and sulphur.
Twenty-three industrial, commercial and government laboratories participated in an interlaboratory measurement program using methods of their own choosing.
ANOVA was used to calculate the consensus values and other statistical parameters from the interlaboratory measurement program. Values are deemed to be Certified if derived from 10 or more sets of data that meet CCRMP statistical criterion regarding the agreement of the results. Fifteen elements were certified (see Table 1).
Gold was determined by various fire assay pre-concentration techniques, often with lead, and followed by atomic absorption spectroscopy, inductively coupled plasma - atomic emission spectrometry, or gravimetric finish; or instrumental neutron activation analysis.
Other elements were determined by various multi-acid and microwave digestions, fusions, combustion - infrared spectroscopy, extractions, iron collection followed by atomic absorption spectroscopy, flow injection mass spectrometry, gravimetric analysis, hydride generation atomic absorption spectroscopy, inductively coupled plasma – atomic emission spectroscopy, inductively coupled plasma - mass spectrometry, or titrations. Both fused and pressed powder pellet were used for X-Ray fluorescence spectrometry. Cold vapour separation was used for mercury.
Full details of all work, including the statistical analyses, the methods and the names of the participating laboratories are contained in the Certification Report. For more details on how to use reference material data to assess laboratory results, users are directed to ISO Guide 33:2000, pages 14-17, and the document, “Assessment of laboratory proficiency using CCRMP reference materials”, at www.ccrmp.ca under Publications, which is based on Guide 33:2000.
Eleven provisional values (Table 2) were derived from 8 or 9 sets of data that fulfill the CCRMP statistical criterion regarding agreement; or alternatively, 10 or more sets of data, that do not fulfill the CCRMP statistical criteria required for certification. Additionally, the statistical analysis of the data warranted provisional status, despite fewer sets, for beryllium and calcium by fusion and, three and four acid digestions. Informational values for 26 elements, shown in Table 3, were derived from the means of a minimum of 3 sets of data.
The values quoted herein are based on the consensus values derived from the statistical analysis of the data from the interlaboratory measurement program, and the standards used by the individual laboratories. The report gives the available details.
DS-1 is a new material.
PERIOD OF VALIDITY
The certified values are valid until March 31, 2030. The stability of the material will be monitored every two years for the duration of the inventory. Updates will be published on the CCRMP web site.