Assaying Ores, Concentrates, and Bullion - State of Arizona ...

*\ nBureau of Mines Information Circuiar/l97700Assaying Ores, Concentrates,and BullionRevision of Information Circular 7695UNITED STATES DEPARTMENT OF THE INTERIORm1maut mop. Ylll(k

Information Circular 8714rAssaying Ores, Concentrates,and BullionRevision of Information Circular 7695By H. H. Heady and K. G. BroadheadUNITED STATES DEPARTMENT OF THE INTERIORCecil D. Andrus, SecretaryBUREAU OF MINES

This publication has been cataloged as follows:Heady, Howard HAssaying ores, concentrates, and bullion. Revision ofinformation circular 7695, by H. H. Heady and K. G. Brwdhead.[Washington] US. Bureau of Mines [1977]26 p. (U.S. Bureau of Mines. Informarion circular 8714r)Includes bibliography.1. Ores-United Stares-Analysis. 2. Precious metals-UnitedSrarcs-Analysis. 3. Testing laboratories-United Srarcs. I.Broadhcad, Kenneth G., jc. aurh. 11. Title. (Series)TN23SJ71 no. 87141 622.06173U.S. Dept. of rhe 1°C. Library

ASSAYING ORES, CONCENTRATES, AND BULLIONRevision of Information Circular 7695byH. H. Heady 1 and K. G. Broadhead2ABSTRACTThis Bureau of Mines report provides specific information regarding theanalysis of ores, concentrates, and bullion. It describes analytical servicesprovided by some Federal agencies, and discusses analytical techniques applicableto the precious metals. The appendixes list Bureau of Mines State LiaisonOffices and cmercial assay laboratories.INTRODUCTIONSharp increases in the world market prices of gold and silver have generateda renewed interest in prospecting and mining. Almost simultaneouslythere has been an upsurge of interest in the platinum-group metals owing notonly to a shortage of these metals but also to prospecting activity--particularlyin the Western United States. Still another factor contributing to thebooming interest in the noble metals is the recent legislation (PublicLaw 93-373) effective December 31, 1974, that permits citizens of the UnitedStates to buy and possess gold. As a result of this situation, many citizensare seeking information and advice regarding investing, prospecting, mining,milling, refining, and analyzing the noble metals.This paper is a revision and updating of Information Circular 7695 (6) .3FEDERAL AND STATE AGENCIESMany mineral samples are sent to Government agencies with the requestthat they be assayed or chemically analyzed. It should be emphasized that -there are no Federal agencies, except for the U.S. Mints, where assays andquantitative analyses are made for the public.Many of the States maintain a Bureau of Mines, a Geological Survey, orsome similar organization, frequently at a State university, where mineralslSupervisory research chemist.2Chemical engineer.3~nderlined numbers in parentheses refer to items in the list of referencespreceding the appendixes of this report.

found by residents of the State will be identified free of charge. Usually,a charge is made for assays. Specific tests, as on clays, are made by someof these offices.The Federal Bureau of Mines, although it attempts to avoid duplicationof services rendered by State agencies, is authorized to give advice regardingprospective markets. It does not compete with private assayers and chemists,but it will accept samples sent to its field laboratories, and identify themby visual or microscopic inspection. This examination is usually sufficientto indicate whether the material has cormnercial value, or at least if theexpense of an assay would be warranted. Except in connection with its owntechnical investigations, no assays or other special tests are made by theBureau of Mines. A general statement of policy regarding the ~ureau's mineralogicalservices that are available to the public is included in the FederalRegister (2).The U.S. Geological Survey and the Smithsonian Institution also makemineral identifications of specimens as a public service. However, neitherof these agencies nor the Bureau of Mines will provide such services on longsuites of specimens submitted by mineral dealers, well drillers, or others,when such work can be done regularly by conrmercial concerns.The U.S. Mint, Denver, Colo., provides assays of ores for gold, silver,copper, lead, and zinc. The U.S. Mints also perform assays of gold and silverbullion. The special services provided, the charges involved, and the locationsof U.S. Mints are presented in the Code of Federal Regulations,Title 31--Money and Finance, published by the Office of the Federal Register,General Services Administration. A copy of this regulation can be obtainedfrom the Superintendent of Documents, U.S. Government Printing Office,Washington, D.C . 20402.PROCEDURE FOR OBTAINING ORE SAMPLESThe economic exploitation of a mineral deposit follows a more or less setsequence. Invariably, the first step is identification to determine whetherthe ore to be mined or the mineral to be sold is actually what it is thoughtto be. An identification is a qualitative examination designed to giveinformation as to what a substance may be rather than how much of it may bepresent.If the identification shows the material to be one of possible commercialvalue, the next step is to take a sample representative of the exposed faceor outcrop for assay or quantitative chemical analysis. Preliminary considerationalso should be given to certain economic aspects. For example, nomineral deposit, irrespective of its size and grade, is of immediate value ifit is so inaccessible that the product cannot be mined, processed, transported,and sold at a profit on a competitive market.Sampling should always be made on a fresh surface. There are twosuggested ways of proceeding, of which the second is the more reliable.

of the bar, is therefore enriched in the lowest melting point metal.Obviously, the best way to sample material of this type would be while it ismolten and homogeneous. Since this is normally impossible except to therefiner, drilling or sawing the bar offer the best alternatives. Sawing ismore laborious and destroys the continuity of the bar since it would have tobe sawed completely through. In drilling the bar, it is important to sampleboth the ends as well as the middle and to drill either completely throughthe bar or to drill half way through from both sides. The material removedfrom the bar must, in turn, be carefully sampled for assay or, in sawcases, remelted and either sampled while molten or frozen rapidly by pouringinto water so that segregation does not occur. Proper sampling of obviouslyheterogeneous metals such as industrial, jewelry, or dental scrap requiresthat the material be melted prior to sampling. The sampling of scrapelectronic parts consisting of circuit boards, and components such astransistors and integrated circuits, is a difficult task and requires anassay on each constituent and an estimate on their total number. It may befeasible in some cases, such as in sampling circuit boards, to roast the sampleto remove the organic material and then analyze the ash for the metalvalues of interest.DESCRIPTION OF TESTING TECHNIQUESVarious testing techniques are available to the public at commerciallaboratories, the choice of which depends on the problem to be solved. Themost useful techniques are described to familiarize the reader with theirapplication as well as their limitations.Chemical AnalysisA chemical analysis is often used to determine how much of a particularelement is present in a sample. Chemical analyses are normally very preciseand accurate, but they are often less sensitive and more time consuming thaninstrumental analyses. It is because of these disadvantages that wet chemicaltechniques are usually not suitable for the determination of the noblemetals (gold, silver, platinum-group metals) in ores and concentrates. Inrecent years, there has been a merging and combining of chemical and instrumentaltechniques to take advantage of the best features of both approaches. .For example, an ore sample might be put into solution and separatedchemically into fractions that are subsequently analyzed for selected elementsby either standard chemical or atomic absorption procedures.The value of a quantitative analysis depends on how representative thesample is of the total bulk of material to be tested. No ore or mineraldeposit is uniform throughout; consequently, an analysis of a sample consistingof a single specimen or a few randomly chosen pieces of rock is uselessin attempting to evaluate a potential deposit. This information can beobtained only by prescribed scientific methods of sampling.

spectra that can be used to identify that particular element. In usualpractice, a very small amount (5 to 50 mg) of finely pulverized ore sample(or filings if the sample is metallic) is vaporized completely, and the resultingspectra is recorded and used to determine the metals present. Thisgeneral procedure can also be used to estimate the approximate concentrationof each metal detected. If necessary, this technique can be further specializedto permit the quantitative determination of selected elements. Thechief advantage of a spectrographic analysis is that 30 to 50 elements canbe readily determined at quite low concentration levels. Consequently, alarge number of samples can be surveyed rapidly to determine their generalelemental composition. An important disadvantage is that most of the noblemetals cannot normally be detected below about 30 parts per million (about1 oz/ton) in ores and concentrates. Another disadvantage in applying thistechnique for detecting precious metals at low concentrations is thepossibility of misidentification due to interferences from other elements inthe sample. Since the usual requirement is to detect noble metals at concentrationlevels as low as 0.01 oz/ton, the spectrographic approach isnot recommended. More specific information on spectrographic analysis maybe gained from a good text such as the one by Aherns and Taylor (l).X-Ray AnalysisIn X-ray fluorescence analysis, the sample is exposed to a highintensitygamma ray or X-ray beam, which causes each element present in thesample to emit characteristic X-rays that can be used to identify therespective elements. The intensity of this secondary X-radiation fran thesample is also directly proportional to the concentration of each elementthat is present. In ordinary practice, a small amount of finely pulverized'sample is placed in the X-ray instrument and excited by the X-ray beam.The whole range of emitted X-rays can be recorded to determine which elementsare present, or X-rays emitted from a particular element can be counted andcompared with those of known standards to determine the exact concentration.The main advantages ofthis X-ray fluorescence technique are that it is simple,rapid, highly reliable, and quite accurate providing proper calibration hasbeen achieved for each type of sample being analyzed. Some disadvantages arethat this technique is matrix-dependent and, consequently, it cannot be usedto determine the metal content of ores, concentrates, or alloys without firstbeing carefully calibrated to handle each particular type of material.Another disadvantage is that most of the noble metals cannot be detected belowabout 50 to 100 parts per million (2 to 3 ozlton). Therefore, this approachis not reconmended for the direct determination of gold, silver, or theplatinum-group metals in ores or concentrates. Liebhafsky, Pfeiffer, Winslow,and Zemany (7) give an excellent discussion on the application of X-rayfluorescence analysis techniques.Another useful tool is X-ray diffraction (8). This technique is basedupon the fact that the crystal structure of any given sample causes theincident X-rays to be diffracted in a manner characteristic of that particularmaterial. The resulting X-ray diffraction pattern is like a fingerprint forthat material, and can be used to identify it even in the presence of othercrystalline materials. Over 20,000 different minerals, metals, and compoundshave been catalogued by their characteristic X-ray diffraction patterns.

The use of this catalogue simplifies the identification of the variouscomponents in any crystalline sample. The advantage of X-ray diffraction isthat it tells something about the composition and structure. Ordinarily,X-ray diffraction is not used to make quantitative determinations. However,in special cases, such as the determination of free silica in a coal mine dustsample, it is feasible to make quantitative analyses.Atomic Absorption AnalysisAtomic absorption is based on the fact that a free atom is capable ofabsorbing light of the same wavelength it would normally emit. If lightemitted by an element inside a special lamp is passed through a gaseous cloudcontaining this element in the atomic state, then the atoms from this element,and only this element, will absorb this light. In practice, the gaseouscloud is formed by aspirating a solution of the sample to be analyzed intoa flame of sufficient temperature to reduce the element to its atomic state.The absorbance of the light from the special lamp by the aspirated samplesolution is then compared with the absorbances of suitable standards analyzedin a similar manner. Prior to analysis, the sample obviously must be putinto solution with suitable solvents. In gold analysis, this can beaccomplished readily with aqua regia, a mixture of nitric and hydrochloricacids. For the analysis of gold and the platinum-group metals, dissolutionand direct analysis of ores or concentrates is impractical; the very smallabsorption signal from the low levels of these metals that are normallyencountered is masked by light scattering in the flame caused by highconcentrations of dissolved solids (4). Consequently, it is necessary toresort to methods involving organic extraction of the precious metals fromthe acid solution and analysis of these extracts, or the use of fire assayto preconcentrate the precious metals into a small bead that can be dissolvedand analyzed by atomic absorption. Using an acid digestion-organic extractionmethod on a 1-gram sample, less than 0.01 ounce of gold per ton of ore maybe measured. If a fire assay preconcentration is used, the sensitivity canbe extended still further. Atomic absorption analysis, when properly applied,has few disadvantages, and it is fast, accurate, and economical. It hasthe advantage that the equipment is comparatively inexpensive. Furthermore,since the method may be employed for the analysis of most metals, manytesting laboratories use this technique. An excellent and comprehensive texton this type of analysis is the one by Ramirez-Muiioz (2).Neutron Activation AnalysisThis method of analysis is based on the principle that when a sampleis subjected to bombardment by neutrons, some of the stable atoms that makeup the sample will absorb neutrons and become radioactive. These radioactiveatoms will, in turn, emit gama rays the energies of which are characteristicof the particular elements. Using suitable and rather sophisticatedelectronic counting equipment, these gam rays can be detected, and theelements and amounts present in the sample can be determined. Alternatively,to obtain greater sensitivity and avoid interferences, the activated samplemay be dissolved and the elements of interest chemically separated prior tobeing counted. For gold and silver, the direct electronic method has

excellent sensitivity, but for the platinum-group metals, chemical separationtechniques are required. This type of analysis would not normally be utilizedfor ores or concentrates. Analysis of the noble metals by this method isusually limited to rather esoteric samples, such as moon rocks, filings fromancient coins, and geological samples with exceedingly small and noneconomicamounts of metals present. Only small samples are usually irradiated innuclear reactors, and consequently any material that is not clearly homogeneous,such as a gold ore, can give erroneous results. Furthermore, themethod is expensive and is only performed commercially in a few laboratories.Bullion AssayThe analysis of gold or silver bullion is more complex, time consuming,and expensive than a standard fire assay. This is readily understandablesince the material the sample represents is very valuable and, therefore,the analysis warrants the utmost attention. Great care must be exercised inobtaining proper samples that are truly representative of the whole material.The assay of gold and silver bullion is expressed in parts per thousand calledfineness. For example, a gold bullion containing 99 percent gold, or 990parts per thousand, is 990 fine.The assay for silver in silver bullion or gold bullion may beaccomplished either by cupellation or by wet chemical volumetric methods.The cupellation method is subject to more errors, and if accurate values areneeded, as in the assay of fine silver bullion, the chemical procedure mustbe applied. The errors in the cupellation assay for silver are corrected bymeans of a check or proof assay of a synthetic sample of approximately thesame weight and composition as the bullion sample. The check and bullionsamples are cupelled side by side, and it is assumed that the losses asdetermined for the check sample also apply to the bullion. Therefore, themethod involves a preliminary assay to determine the approximate compositionof the bullion before the check assay can be prepared. The sample sizenormally taken is about one-half gram. The assay of fine silver bullion,greater than 990 fine, is normally accomplished by a wet chemical procedurecalled the "Gay Lussac--U.S. Mint Method" Q). In this technique, the silversample, about 1 gram, is accurately weighed, dissolved in nitric acid, andabout 99.8 percent of the silver is precipitated with a 100-ml NaCl solutionthat has been previously standardized with pure silver. Subsequent milliliteradditions of the diluted standardized NaCl solution are added until nofurther precipitation occurs. A more recent refinement of this method usesatomic absorption to determine the small amount of silver remaining in solutionafter the initial precipitation with the standardized NaCl solution.The general method of assaying gold bullion is by cupellation and partingaccompanied by check or proof assays on synthetic alloys corresponding to thecomposition and weight of the bullion (2,-10). Therefore, the method usuallyrequires a preliminary assay to obtain an approximate analysis. As in thecase of silver bullion analysis, the check and bullion samples are cupelledside by side, and any loss or gain in the check sample, which is called thesurcharge, is applied to the bullion sample. In the parting process, whichseparates the silver from the gold, the silver-gold ratio must be kept between

2 to 4 parts silver to 1 part gold, otherwise proper parting will not beachieved. Consequently, silver must normally be added to both the bullionand proof sample. The resulting bead from the cupellation must be rolledvery thin and parting procedure must be carefully standardized. In boththe silver and gold bullion assay, results are obtained on duplicate samples.PRICES AND FEESThe trade generally recognizes three qualities of work. The first andlowest priced analysis is designated by such terms as routine, engineer'ssurvey, and preliminary. A higher priced, more careful analysis is calledcontrol, and third and most expensive is called umpire. Unfortunately,there is no way of setting up standards of quality on the basis of accuracybecause sane elements, such as iron or copper, can be determined in theusual samples with little effort to a high degree of accuracy, whereas othersrequire time-consuming procedures and great skill, in spite of which accuracyof results is only fair.The price ranges listed are typical of the prices being quoted by conrmercia1laboratories as of January 1, 1977, for routine analyses. The listedvalues are for single, finely ground samples. An extra charge of $1 to $51per sample is assessed if the sample has to be prepared for analysis.Discounts are usually granted if many samples of the same type are submittedat one time.:;Atomicabs;;ionGold ....................... $4- $8 $3-$7Silver.. ................... 4- 8Gold and silver........ ....Platinum ................... 20-l70 25-35Higher prices are charged for the assay of the richer samples, such asbullion, sweepings, and jewelry. Control and umpire analyses cost two tothree times the price of routine analyses.A qualitative spectrographic analysis to determine the general elementalcomposition costs about $15 to $30 per sample. An X-ray diffraction analysisto determine the mineral composition of a sample costs about $30 to $50.Most of the cmon metals in ores, concentrates, and alloys can bedetermined with reasonable accuracy by atomic absorption. The cost is $1.50to $3 for the first element, plus about $1 to $2 for each succeeding elementin the same sample. S m of the metals that can be determined by this techniqueare bismuth, cadmium, chromium, cobalt, copper, iron, lead, manganese,molybdenum, nickel, tin, and zinc.

A few laboratories perform mineralogical services. the cost of whichvaries with the type of analytical work required . Typical services andestimated costs are as follows:Petrographic and mineralogical examination per hour ...... $10Thin sections ................................ p er sample .. $4- 14Polished sections ................................ do.. . 4- 15Grain mounts ..................................... do ...... 4- 10Particle size distribution ....................... do ...... 25- 35Specific gravity ................................. do . 4- 6

REFERENCESAherns , L. H. , and S. R. Taylor. Spectrochemical Analysis. Addison-Wesley Publishing Co., Inc., Reading, Mass., 2d ed., 1961, 429 pp.Broadhead, K. G., B. C. Piper, and H. H. Heady. Fire Assay-EmissionSpectrographic Determination of Iridium, Ruthenium, and Osmium. Appl.Spectr., v. 26, No. 4, 1972, pp. 461-467.Bugbee, E. E. A Textbook of Fire Assaying. John Wiley & Sons, Inc. ,New York, 3d ed., 1940, p. 221.Elliott, E . V. , and K. R. Stever.Problems in Determining the NobleMetals in Ores. Atomic Absorption Newsletter, v. 12, No. 3, 1973,pp. 60-62.Furman, N. H. (ed.). Standard Methods of Chemical Analysis. D. VanNostrand Co. Inc., Princeton, N.J., 6th ed., 1966, pp. 985-988.Klahold, B. R. Laboratories That Make Fire Assays, Analyses, and Testsof Ores, Minerals, Metals, and Other Inorganic Substances. BuMinesIC 7695, 1954, 20 pp.Liebhafsky, H. A., H. G. Pfeiffer, E. H. Winslow, and P. D. Zemany.X-Ray Absorption and Emission in Analytical Chemistry. John Wiley& Sons, Inc., New York, 1960, 357 pp.Nuffield, E. W. X-Ray Diffraction Methods. John Wiley & Sons, Inc.,New York, 1966, 409 pp.Ramirez-Muibs, J. Atomic Absorption Spectroscopy.Co. , New York, 1968, 495 pp.Elsevier PublishingShepard, 0. C. , and W. F. Dietrich. Fire Assaying. McGraw-Hill BookCo. , Inc. , New York, 1940, 277 pp.U.S. Bureau of Mines. Policy Statement on Mineralogical Services.Federal Register, v. 40, No. 134, July 11, 1975, p. 29308.Whitehead, A. B., and H. H. Heady. Fire-Assay Emission SpectrographicMethod for Platinum, Palladium, Rhodium, and Gold. Appl. Spectr.,v. 24, No. 2, 1970, pp. 225-228.

APF'ENDIX A.--STATE LIAISON OFFICESLocal InformationThe U.S. Department of the Interior has established, through its Bureauof Mines, State Liaison Officers to represent each of the States and territories.The primary mission of these Officers is to conduct the Bureau'sbusiness that can best be accomplished at the State and local levels, toinsure participation of appropriate organizations within the State in actionsof mutual concern, and to serve as a Federal point of contact. The LiaisonOfficers are familiar with the mining and metallurgical activities in theirparticular geographical areas. Accordingly, they are available to provideinformation and advice to private citizens and people in industry who areinterested in prospecting, mining, milling, refining, and analyzing preciousmetals. The attached list of State Liaison Officers is provided as a matterof general interest and service to the public.Bureau of Mines, U.S. Department of the Interior,Liaison Program Office DirectoryAlabamaState Liaison OfficeArkansasState Liaison OfficeBureau of MinesBureau of MinesU.S. Department of the Interior U.S. Department of the InteriorP.O. Box LRoom 3331, Federal Office Bldg.University, Ala. 35486 Little Rock, Ark. 72201(205) 758-0491 (501) 378-5965AlaskaState Liaison OfficeCaliforniaState Liaison OfficeBureau of MinesBureau of MinesU.S. Department of the Interior U.S. Department of the InteriorRoom G-81, Federal Bldg. Room 3046Anchorage, Alaska 99501 650 Capitol Mall(206) 442-0151 Sacramento, Calif. 95814(916) 440-2417ArizonaState Liaison OfficeColoradoBureau of MinesState Liaison OfficeU.S. Department of the Interior Bureau of MinesRoom 1012U.S. Department of the Interior2721 North Central Ave. Room 820, Bldg. 67Phoenix, Ariz . 85004Denver Federal Center(602) 261-3357 Denver, Colo. 80225(303) 234-4205

ConnecticutSee New HampshireDelawareSee MarylandFloridaState Liaison OfficeBureau of MinesU.S. Department of the InteriorRoom 204547 North Monroe St.Tallahassee, Fla. 32301(904) 222-6218GeorgiaState Liaison OfficeBureau of MinesU.S. Department of the InteriorRoom 43119 Martin Luther King, Jr., Dr., SWAtlanta, Ca. 30334(404) 221-6204HawaiiSee CaliforniaIdahoState Liaison OfficeBureau of MinesU.S. Department of the InteriorRoom 2034620 Overland Rd.Boise, Idaho 83705(208) 384-1084IllinoisState Liaison OfficeBureau of MinesU.6. Depsrtmnt of the InteriorRoom 102, Jefferson West No. 1525 W. Jefferson St.Springfield, Ill. 62702(217) 525-4368IndianaState Liaison OfficeBureau of MinesU.S. Department of the InteriorRoom 113Seventh and College Sts.Bloomington, Ind. 47401(812) 339-6139- IowaSee MissouriKansasState Liaison OfficeBureau of MinesU.S. Department of the InteriorSuite 220, Federal Bldg./U.S. Courthouse444 S .E. QuincyTopeka, Kans. 66603(913) 295-2520KentuckyState Liaison OfficeBureau of MinesU.S. Department of the InteriorRoom 269John C. Watts Federal Bldg.330 West BroadwayFrankfort, Ky . 40601(502) 875-4120LouisianaState Liaison OfficeBureau of MinesU.S. Department of the InteriorRoom 119, Federal Bldg. andCourthouse707 Florida St.Baton Rouge, La. 70801(504) 387-0181, ext. 374-MaineState Liaison OfficeBureau of MinesU.S. Department of the InteriorP.O. Box 228Augusta, Maine 04330(207) 622-6171, ext. 292

MarylandState Liaison OfficeBureau of MinesU.S. Department of the InteriorColumbia PlazaRoom 9072401 E St., N.W.Washington, D.C. 20241(202) 634-1272MassachusettsSee New HampshireMichiganState Liaison OfficeBureau of MinesU.S. Department of the InteriorRoom 1121, C-rce Center Bldg.300 Capitol St.Lansing, Mich. 48933(517) 372-1910, ext. 681MinnesotaState Liaison OfficeBureau of MinesU.S. Department of the InteriorP.O. Box 1660Twin Cities, Minn. 55111(612) 725-4535MississippiState Liaison OfficeBureau of MinesU.S. Department of the InteriorRoom 408, 301 Bldg.301 North Lamar St.Jackson, Miss. 39202(601) 969-4208MissouriState Liaison OfficeBureau of MinesU.S. Department of the InteriorP.O. Box 1187Rolla, Mo. 65401(314) 364-5555MontanaState Liaison Of £iceBureau of MinesU.S. Department of the Interior636 North LoganHelena, Mont. 59601(406) 449-5297NebraskaSee KansasNevadaState Liaison OfficeBureau of MinesU.S. Department of the InteriorRoom 306, Post Office Bldg.705 North Plaza St.Carson City, Nev. 89701(702) 882-9380New HampshireState Liaison OfficeBureau of MinesU.S. Department of the InteriorPost Office and Federal Bldg.Newmarket, N .H. 03857(603) 659-3101New JerseySee PennsylvaniaNew MexicoState Liaison OfficeBureau of MinesU.S. Department of the InteriorRoom 104, U.S. Courthouse/Federal Bldg .Santa Fe, N. Mex. 87501(505) 988-6624New YorkState Liaison OfficeBureau of MinesU.S. Department of the InteriorSuite 2031659 Central Ave.Albany, N.Y. 12205(518) 869-9536

North CarolinaState Liaison OfficeBureau of MinesU.S. Department of the InteriorP.O. Box 2828Raleigh, N.C. 27602(919) 755-4166North DakotaState Liaison OfficeBureau of MinesU.S. Department of the InteriorRoom 7, 207 E. BroadwayBismarck, N. Dak. 58501(701) 255-4011, ext. 378- OhioSee IndianaOklahomaState Liaison OfficeBureau of MinesU.S. Department of the Interior168 Post Office Bldg.N.W. Third St.Oklahoma City, Okla. 73102(405) 231-4521OregonState Liaison OfficeBureau of MinesU.S. Department of the InteriorSuite 7, Standard Insurance Bldg.475 Cottage St., NESalem, Oreg. 97301(503) 399-5755PennsylvaniaState Liaison OfficeBureau of MinesU.S. Departmnt of the InteriorP.O. Box 783Federal Square StationHarrisburg, Pa. 17108(717) 782-4474Puerto RicoSee FloridaRhode IslandSee New HampshireSouth CarolinaState Liaison OfficeBureau of MinesU.S. Department of the Interior403 Columbia Bldg.Main and Gervais Sts.Columbia, S.C. 29201(803) 765-5561South DakotaState Liaison OfficeBureau of MinesU. S. Department of the InteriorRoom 261, Federal Bldg.,U.S. Courthouse515 Ninth St.Rapid City, S. Dak. 57701(605) 342-1950TennesseeState Liaison OfficeBureau of MinesU.S. Department of the Interior1109 Parkway Towers404 James Robertson ParkwayNashville, Tenn. 37219(615) 749-7254TexasState Liaison OfficeBureau of MinesU.S. Department of the InteriorRoom 782, Federal Bldg.Austin, Tex. 78701(512) 397-5781-UtahState Liaison Of £iceBureau of MinesU.S. Department of the Interior1600 East First South St.Salt Lake City, Utah 84112(801) 524-5383VermontSee New HampshireVirginiaSee North Carolina

WashingtonState Liaison OfficeBureau of MinesU.S. Department of the InteriorRoom 205Evergreen Plaza Bldg.711 S. Capitol WayOlympia, Wash. 98501(206) 753-9445West VirginiaState Liaison OfficeBureau of MinesU.S. Department of the InteriorP.O. Box 428Charleston, W. Va. 25322(304) 343-6181, ext. 443WisconsinSee MinnesotaWyomingState Liaison OfficeBureau of MinesU.S. Department of the InteriorP.O. Box 1796Cheyenne, Wyo. 82001(307) 778-2220, ext. 2481Headquarters OfficeWashington, D.C.Chief, State Liaison Program OfficeBureau of MinesU.S. Department of the InteriorRoom 901, Columbia Plaza2401 E St., N.W.Washington, D .C . 20241(202) 634-1272

APPENDIX B.--COMMERCIAL ASSAY LABORATORIESThe following listing of assay laboratories, arranged alphabetically byState, is compiled as a public service. This listing does not necessarilyinclude every conunercial laboratory in each State, nor does the Bureau ofMines vouch for or recmnd these laboratories wer any others.AlabamaSouthern Testing Laboratories129 West valleyU~ve.Birmingham, Ala . 35209Vester J. Thompson, Jr., Inc.Box 9253Mobile, Ala. 36609AlaskaAlaska Minerals and MaterialsLaboratory3944 Spenard Rd.Anchorage, Alaska 99503Alaska Testlab4040 B St.Anchorage, Alaska 99503Chemical & Geological Laboratoriesof Alaska, Inc.P.O. Box 4-1276Anchorage, Alaska 99509Resource Associates of Alaska, Inc.3230 Airport Rd.Fairbanks, Alaska 99701ArizonaAmerican Analvtical & ResearchLaboratories3441 East Milber St.Tucson, Ariz. 85714Arizona Testing Laboratories815 West MadisonPhoenix, Ariz . 85007Iron King Assay OfficeIron King MineP.O. Box 14Humbolt, Ariz . 86329Jacobs Assay Office1435 South 10th Ave.Tucson, Ariz. 85713Rochin Assay Office Inc.P.O. Box 1323Douglas, Ariz. 85607Skyline Labs Inc.Hawley & Hawley Division1700 West Grant Rd.Tucson, Ariz. 85705Southwestern Assayers &Chemists , Inc .710 East Evans Blvd.Tucson, Ariz. 85713Valley Assay Office1010 LemonTempe, Ariz. 85281ArkansasNoneCaliforniaAIMS, Inc.1360 Bayport Ave.San Carlos, Calif. 94070Abbot A. Hanks , Inc .115 Indiana St.San Francisco, Calif. 94107Caltest Analytical Laboratories20 McDonnelSonama, Calif. 95476Clarkson Laboratory & Supply, Inc.1144 30th St.San Diego, Calif. 92102

Robert E. Craig & CompanyP.O. Box 577Sun Valley, Calif. 91352Eisenhauer LaboratorieslllOA East Edna PI.Covina , Calif. 91724GMG Assay Office432 West Main St.Quincy , Calif. 95971Heavy Metals Laboratories1415 Colorado St.Santa Monica, Calif. 90404John D. HessTesting Corp.356 East Main St.El Centro, Calif. 92243Humel & Christianson ConsultingEngineers102 East AlisoOjai, Calif. 93023J & J Smelting & Refining Corp.17474 CatalpaP.O. Box 727Hesperia, Calif. 92345Kem ' s14039 East Don Julio Rd.La Puente, Calif. 91747Metallurgical Laboratories, Inc.1142 Howard St.San Francisco, Calif. 94103Miles D. Rombough Laboratories3069 Del Paso Blvd.Sacramento, Calif. 95815Minerals Engineering417 South Hill St. Room 1099Los Angeles , Calif. 90013Morse Laboratories1525 Fulton Ave.Sacramento, Calif.95825Ralph E. Pray, D.Sc.Mining & Metallurgy ResearchLaboratories40 North Sycamore Ave.Pasadena, Calif. 91107Quality Control Laboratories2606 North DurfeeEl Monte, Calif. 91732Reed Engineering1140 North Lemon St.Orange, Calif. 92667San Joaquin Research Laboratories2253 South El DoradoStockton, Calif. 95206Twining Laboratories, Inc.2527 Fresno St.Fresno, Calif. 93721Twining Laboratories of So. Calif.,Inc .3310 Airport WayLong Beach, Calif. 90801Wilkinson Assays9491 Sierra Ave.Fontana, Calif. 92335ColoradoAccu-Labs Research, Inc.11485 West 48th Ave.Golden, Colo. 80401Alan D. Breese, Sr.1947 South Decatur St.Denver, Colo. 80219Brown Laboratory2263 BroadwayGrand Junction, Colo. 81501CDC Associates, Inc.5401 Western Ave.Boulder, Colo. 80301Colorado Analytical Laboratory240 South MainBrighton, Colo. 80601

Colorado Assaying Company2244 BroadwayDenver, Colo . 80205Colorado School of Mines ResearchInstituteP.O. Box 112Golden, Colo. 80401Coors Spectro-Chemical LaboratoryDivision of Coors Porcelain Co.600 NinthGolden, Colo. 80401Ernest Engineering Co.734 East Second Ave.Durango, Colo. 81301Fluo-X-Spec Analytical Laboratory718 Sherman St. (rear)Denver, Colo. 80203G X Labs, Inc.16948 South Golden Rd.Golden, Colo. 80401Grand Junction Laboratories439 North Ave.Grand Junction, Colo. 81501Thomas E. Hancock120 South WalnutHayden, Colo. 81639Hazen Research, Inc .4601 Indiana St.Golden, Colo. 80401Mile High PlacersP.O. Box 483Golden, Colo. 80410Minerals Assay Laboratory549 Noland Ave .Grand Junction, Colo. 81501Natural Resources Laboratory1100 SinnnsLakewood, Colo .Mailing address:P.O. Box 702Edgemont BranchGolden, Colo. 80401Herbert M. Ochs81 South Elati St.Denver, Colo. 80223Charles 0. Parker & Co.William Bealer, Owner2114 Curtis St.Denver, Colo. 80205Root and NortonWest Animas ValleyDurango , Colo . 81301Root and Simpson, Inc.1310 East 17th Ave.Denver, Colo. 80218Skyline Labs, Inc.12090 West 50th PI.Wheatridge, Colo. 80033Specomp Services, Inc .917 Lincoln Ave.Steamboat Springs, Colo. 80477George Treder Assayer1413 Idaho SpringsIdaho Springs, Colo. 80452ConnecticutYork Research Corp.1 Research Dr.Stamford, Conn. 06904DelawareBrandt Associates Inc.50 Blue Hen Dr.Newark, Del. 19713Lehight Testing Laboratories, Inc.P.O. Box 1241Wilmington, Del. 19898FloridaTechnical Services Inc.P.O. Box 52329Jacksonville, Fla . 32207Thornton Labs, Inc .1145 East Cass St.Tampa, Fla. 33601

GeorgiaDunn Laboratories, Inc.717 Edgehill Ave. , NWAtlanta, Ga. 30318Law & Company635 Angier Ave. , NEAtlanta, Ga. 30308McMillan Research1221 Barclay Circle, SEMarietta, Ga. 30060Metallurgical Engineers of Atlanta3480 Oakcliff Rd.Doraville , Ga. 30340HawaiiNoneIdahoBoise Assayers & Metallurgy1519 MainBoise, Idaho 83706Idaho Assaying & Metallurgy707 North 27thBoise, Idaho 83702Peter Mack166 KingWallace, Idaho 83873Silver Valley Laboratory308 North TaylorOsburn, Idaho 83849IllinoisCharles C. Kawin Company2671 GardnerBroadview, Ill. 60153Chicago Spectro ServicesLaboratories, Inc .4846 South KedzieChicago, Ill. 60632Commercial Testing and EngineeringCompany228 North LaSalleChicago, Ill. 60601Factory Standards Laboratory, Inc.416 North State St.Chicago, 111. 60610Pittsburgh Testing Laboratory4418 RooseveltHillside, Ill. 60612Robert W. Hunt Company810 South ClintonChicago, Ill. 60607Scientific Control Laboratories,Inc .3136 South KolinChicago, Ill. 60623Taussig Metallurgical Associates,Inc .6955 North HamlinChicago, Ill. 60645IndianaATEC Associates of Indiana5150 East 65th St.Indianapolis, Ind. 462200 A Laboratories, Inc.1437 Sadlier Circle, West DriveIndianapolis, Ind. 46239Sherry John M.2112 Kilgore Ave.Muncie , Ind . 47304Laboratories- IowaAnalytical and Testing Laboratories7004 CarpenterDes Moines, Iowa 50311Patzig Testing Labs, Inc.2215 IngersollDes Moines, Iowa 50311Twin City Testing and EngineeringLabs, Inc .529 LoganWaterloo, Iowa 50703

KansasArrow Laboratories, Inc.123 W. 12thWichita, Kans . 67201Means Laboratories, Inc.419 N. HandleyWichita, Kans . 67213Topeka Testing Laboratories101 N. KansasTopeka, Kans. 66603KentuckyFrazier s LaboratoryMarion, Ky. 42064LouisianaGulf South Research Institute7700 GSRI Ave.Baton Rouge, La. 70808Hydro-Chem Analytical1020 Florida St.Baton Rouge, La. 70802Kem-Tech Labs16550 Highland Rd.Baton Rouge, La. 70808Shilstone Testing Lab, Inc.814 Conti St.New Orleans, La. 70112MaineJohn S. Cunnnings , Inc .Bangor International AirportBangor, Maine 04401MarylandPenniman and Brme, Inc .6252 Falls Rd.Baltimore Md. 21209MassachusettsArnold Green Testing Laboratories, Inc.East Natick 1ndustrIal Park6 Huron Dr.Natick, Mass. 01760Arnold Green Testing Laboratories, Inc.2 Millbury St.Auburn, Mass. 01501Arnold Green Testing Laboratories, Inc.98 Paris St.Everett, Mass. 02149Arnold Green Testing Laboratories, Inc.Springfield, Mass. 01104J. Dirates & Co., Inc.Notre Dame St.Westfield, Mass. 01085Eastern Smelting & Refining Co.37 Bubier St.Lynn, Mass. 01903Skinner & ShemanNew England Laboratories227 California St.Newton, Mass. 02195MichiganDetroit Testing-Laboratory8720 NorthendOak Park, Mich. 48237Michigan Technological UniversityInstitute of Mineral ResearchHoughton, Mich. 4993 1MinnesotaLerch Brothers, Inc.P.O. Box 8Hibbing , Minn. 55746Strasburger and Siege11403 Eutaw PI.Baltimore, Md. 21217

MississippiBrown-Agee Laboratories ofMississippi879 Foley St.Jackson, Miss. 39202Environmental Protection Systems106 Upton Dr.Jackson, Miss. 39209Micro-Methods , Inc .5106 Telephone Rd.Pascagoula , Miss. 39567Mississippi State Chemical LabP.O. Box 2198Mississippi State, Miss. 39762Southern Technical Services, Inc.1627 Westhaven Blvd.Jackson, Miss. 39209MissouriBruce Williams Laboratories620 Joplin St.Joplin, Mo. 64801General Testing Laboratories1517 WalnutKansas City, Mo. 64108Industrial Testing Laboratories2350 South Seventh Blvd.St. Louis, Mo. 63104St. Louis Testing Laboratories2810 Clark Ave.St. Louis, Mo. 63103MontanaButte Minerals LaboratoriesP.O. Box 3867600 East AluminumButte, Mont . 59701Frontier LaboratoriesP.O. Box 159Melrose , Mont . 59743Northern Testing Laboratories, IncP.O. Box 411600 South 25th St.Billings, Mont. 59103Western LaboratoriesP.O. Box 5373131 Airport Rd.Helena, Mont. 59601Yapuncich, Sanderson & BrownLaboratories13 North 32dBillings, Mont. 59101NebraskaHarris Laboratories. Inc.624 Peach St.Lincoln, Neb. 68502Nebraska Testing Laboratories4453 South 67th St.Omaha, Neb. 68117Omaha Testing Laboratories2917 DouglasOmaha, Neb. 68102NevadaHumboldt Geochemical Lab744 South 5thElko, Nev. 89801Humboldt LaboratoriesGrass Valley Rd.Winnemucca , Nev. 89445Nevada Assay Office5800 Reno HighwayFallon, Nev. 89406Foundation & Materials Consultants, Nevada Testing Laboratories LTDInc .300 Boston Ave.839 Front St. Las Vegas, Nev. 89104Helena, Mont. 59601

Rocky Mountain Geochemical Corp. Silver City Testing Laboratories, Inc.840 Greg 1024 Hudson St.Sparks, Nev. 89431 Silver City, N. Mex. 88061Edward S. Shedd939 West RobinsonCarson City, Nev. 89701Silver State Minerals Testing Lab6274 East Charleston Blvd.Las Vegas, Nev. 89122Weideman's Mining Laboratory3160 Deer Run Rd.Carson City, Nev. 89701New HampshireNoneNew JerseyInternational Testing Labs580 Market St .Newark, N. J. 07105Ledoux & Company359 Alfred Ave.Teaneck, N.J. 07666Standard Testing Labs309 Cortlandt St.Belleville, N.J. 07109U.S. Testing Co., Inc.1415 Park Ave .Hoboken, N.J. 07030New MexicoAlbuquerque Assay Laboratory4115 Silver Ave., SEAlbuquerque, N. Mex. 87108Grants Assay Lab1400 West Santa Fe Ave.Grants, N. Mex. 87020Martin and Carlisle ChemicalLaboratory715 San Mateo Blvd., NEAlbuquerque, N. Mex. 87108New YorkHarmnerschlae. Moe Inc .158 Canal s;.New York, N.Y. 10013Hoover & Strong Inc.119 West Tupper St.Buffalo, N.Y. 14201Pitkin Lucius Inc.50 Hudson St.New York. N.Y. 10013Rodman & Yaruss Refining Co. Inc.17 West 47th St.New York, N.Y. 10036North CarolinaFroehling & Robertson, Inc.P.O. Box 2058Asheville , N.C. 28802Law Engineering Testing Co.P.O. Box 18288Raleigh, N.C. 27609Southern Testing and ResearchLaboratoriesP.O. Box 350Wilson, N.C. 27893North DakotaNone-OhioCTL Eneineerine. Inc.2860 ~Ysher R ~ TColumbus, Ohio 43204Crobaugh Laboratories3800 Perkins Ave.Cleveland, Ohio 44114National Spectrographic Laboratories,Inc .19500 South MilesCleveland, Ohio 44128

Wadsworth Testing LaboratoryP.O. Box 2081600 Fourth St. , SECanton, Ohio 44701OklahomaRockwell InternationalTulsa DivisionAnalytical Laboratories2000 N. Memorial Dr.Tulsa, Okla. 74115Southwell Labs1838 S .W. 13thOklahoma City, Okla. 73108United States Testing Co., Inc.1341 N. 108 East Ave.Tulsa, Okla. 74116OregonDepartmnt of Geology and MineralIndustries1069 State Office Bldg.Portland, Oreg. 97201Lawre L. Hoagland7018 SE 17th St.Portland, Oreg. 97202Montana Assay Office610 SW Second St.Portland, Oreg. 97201PennsylvaniaAllentown Testing Lab. Inc.754 E . Fairview St.Bethlehem, Pa. 18108Ambric Testing Labs4041 Ridge Ave.Philadelphia, Pa. 19129Booth Garret Blair180 S. Main St.Ambler, Pa. 19002Conwell E. L. & Co.2024 Arch St.Philadelphia, Pa. 19103General Testing Labs. Inc.241 S. JeffersonAllentown, Pa. 18102Materials Consultants and Laboratories,Inc .1567 Old Abers Creek Rd.Monroevil le , Pa. 15146McCreath Labs. Inc.236 Liberty Ave.Harrisburg, Pa. 17101Pittsburgh Testing Laboratory850 PoplarPittsburgh, Pa. 15220Smith Rudy & Co.20 N. 3d St.Philadelphia, Pa. 19109Spectrochemical Laboratories, Inc.8350 Frankstown Rd.Pittsburgh, Pa. 15221Rhode IslandArnold Greene Testing Laboratories, Inc.15 Bellows St.Warwick, R.I. 02888South CarolinaCommonwealth Laboratory, Inc .112 Greenacre Rd.Greenville , S .C. 29607Environmental Analytics , IncP.O. Box 21427Columbia, S.C. 29221Industrial NDT Co. Inc.3409 Spruill Ave.Charleston, S .C. 29405South DakotaWhitewood AssayersBox 299Whitewood, S. Dak. 57793

TennesseeAtek Labs, Inc .P.O. Box 38Corryton, Tenn. 37721Environmental Science & Engineering,Inc .Mays Chapel Rd.Mt. Juliet, Tenn. 37122Steward Laboratories, Inc .5815 Middlebrook PikeKnoxville, Tenn. 37921Technical Laboratories, Inc.515 Cherokee Blvd.Chattanooga, Tenn. 37405TexasDickinson Laboratories201 North ClarkEl Paso, Tex. 79905Western Weighers, Subsidiary ofHawley & HawleyAssayers & Chemists, Inc.P.O. Box 3471El Paso, Tex. 79923- UtahAmerican Chemical and ResearchLaboratories32 East 3335 SouthSalt Lake City, Utah 84115Chemical and Mineralogical Services445 West 2700 SouthSalt Lake City, Utah 84115Crismon and Nichols440 South 500 WestSalt Lake City, Utah 84101Material Research, Inc.1380 South West Temple St.Salt Lake City, Utah 84115Rocky Mountain Geochemical Corp.1323 West 7900 SouthWest Jordan, Utah 84084Rogers Research and Analysis, Inc68 South Main St.Salt Lake City, Utah 84101Tay Con Laboratories2040 Fortune Rd.Salt Lake City, Utah 84104Union Assay Office , Inc .269 Brooklyn Ave .Salt Lake City, Utah 84101Ute Research Laboratories40 North 400 WestSalt Lake City, Utah 84116VermontNoneVirginiaComnercial Testing & Ennineerine: - - Co.1825-31 Lindsay ~ ce.Norfolk, Va. 23504Froehling & Robertson, Inc.P.O. Box 27524Richmond, Va. 23261Law Engineering Testing Co.P.O. Drawer QQMcLean, Va. 22101Penniman 6 Browne , Inc .1725 Arlington Rd.Richmond, Va. 23230Washington Testing Inc.2930 Eskridge Rd.Fairfax, Va. 22030WashingtonBennetts Chemical Laboratory. -. Inc .901 South Ninth St.Tacoma, Wash. 98405J. M. Knisely Engineering Corp.5807 Fourth Ave., SouthP.O. Box 3724Seattle, Wash. 98124

Laucks Testing Laboratories, Inc.1008 Western Ave .Seattle, Wash. 98104Rocky Mountain Geochemical Corp.6319 North Helena St.Spokane, Wash. 99207Tacoma Assay Office518 Security Bldg.Tacoma, Wash. 98402Technical Service LaboratoriesNorth 1003 Washington St.Spokane, Wash. 99201WisconsinNoneWyomingChemical and Geoloaical - Laboratories420 W. 1st St.Casper, Wyo. 82601Natural Resources Research InstituteCollege of EngineeringUniversity of WyomingBox 3038, University StationLaramie, Wyo. 82070West VirginiaCnmnercial Testing & Engineering Co.626 Broad St.Charleston, W. Va. 25323U.S. GOVERNMENT PRINTING OFFICE: 1977-703-001182