I ll IMLAI Mineral Land Assessment I Open File Report/1994 I MINERAL APPRAISAL OF CORONADO I NATIONAL FOREST, PART 11 Whetstone Mountains Unit Cochise and Pima Counties, Arizona Whetstone Mountains Unit ARIZONA / I E5 I ,.~,~ i~,~,~.~:~J~~ ~ - ~-~. ..... I 1 BUREAU OF MINES UNITED STATES DEPARTMENT OF THE INTERIOR I RE]~RT D(OUMEK11"ATiONPAGE i 1" R~J~,, ~°" 12. 4. ~ and Subtitle Relx~t ~'~rta Mineral appraisal of Coronado National Forest, part ii November 1993 I Whetstone Mountains Unit, Cochise & Pima Co., AZ I Mark L. Chat~n .,o U.S. Bureau of Mines, IFOC-Resource Evaluation Branch I P.O. Box 25086 IL COCTtmCtO~ Or Grunt(G) No. Denver, CO 80225-0086 (C3 (G) I 12. Saonso4r~n( Oqam~ Nm~e end Add:rm~ 13- TYPe o~ R4moTt & lqmod C~v~md Open file report I .14. I 15. Su~p4em~txTy Nottm Z~Ab,~(Un~O.~x~ This report addresses the 44,345-acre Whetstone Mountains Unit of the I Forest. The work included inventorying and mapping of mines and prospects. Rock-chip samples from mineral zones were assayed; assay data are tabulated. Meta~i'ic "mineral deposits are genetically and spatially related to two intrusions that cut or underlie I Paleozoic-age sedimentary rocks. One deposit is a 22 million short ton inferred resource of 0.31 percent copper in veinlets and disseminations of sulfide minerals;-past production has been very small. A Precambrian-agequartz-monzonite/alaskite intrusion hosts a I fluorite vein, several quartz-tungsten veins, and sparse, uraniferous fractures. No re- sources of those commodities are present. A massive quartz dike, probably syngenetic with the Precambrian intrusion of quartz-monzonite/alaskite, was mined for about 300,000 short tons of copper-smelter flux; at least 8 million short tons of indicated silica-flux resources remain, but development is unlikely because they lack any appreciable precious metals content, a requisite in current markets. Sedimentary strata.~ost 137,000 short tons of low-purity, indicated, subeconomic gypsum resources with limited application. They are unlikely to ever be developed, based on steep terrain and unfavorable geologic structure, which would increase mining costs and reduce recoverability. Z~ Oocumem AM~ ~ Oe~c~xo4-s minerals mineral economics copper gypsum fluorite sulfide deposits gold tungsten Lone Star fluorite mine silica flux mine inventory b, Idm~Ufl~ra/Ope~d[ndGd Terms c. COATI Fle4dlGr~= 18. Av~la~lK'y 8~.xtm,rue~. 1~ S~cy CINm (Th~ Rmoo~ 7-I. No. of ~ "~ SGam'~'y C1xmm ~1'~s ~ j MINERAL APPRAISAL OF CORONADO NATIONAL FOREST, PART 11 I WHETSTONE MOUNTAINS UNIT I COCHISE AND PIMA COUNTIES, ARIZONA I I by I MARK L. CHATMAN U.S. BUREAU OF MINES MLA 2-94 I 1994 I I Intermountain Field Operations Center Denver, CO U.S. DEPARTMENT OF THE INTERIOR Bruce Babbitt, Secretary BUREAU OF MINES Hermann Enzer, Acting Director I iiiiI PREFACE I A January 1987 Interagency Agreement among the U.S. Bureau of Mines (USBM), U.S. Geological Survey, and the U.S. Dep. of Agriculture, Forest Service I describes the purpose, authority, and program operations for forest-wide studies. The program is intended to assist the Forest Service in incorporating mineral resource data into forest plans as specified by the National Forest Management Act (1976) and Title I 36, Chapter 2, Part 219, Code of Federal Regulations, and to augment the USBM's mineral resource data base so that it can analyze and make available minerals I information as required by the National Materials and Minerals Policy, Research and Development Act (1980). This report is based upon available information, extensive field investigations to verify or collect additional information, and contacts with mine I operators and prospectors active on lands administered by the Coronado National I Forest. I This open-file report summarizes the results of a USBM forest-wide study. The report is preliminary and has not been edited or reviewed for conformity with the USBM editorial standards. This study was conducted by personnel from the Intermountain Field Operations Center, P.O. Box 25086, Building 20, Denver Federal Center, Denver, CO 80225-0086. I CONTENTS I SUMMARY ............................................... 1 I INTRODUCTION ............................................ 2 Geographic setting ..................................... 2 Geologic and mineral setting .............................. 2 I Mining and prospecting history ............................ 4 Previous investigations .................................. 5 I Present investigation ................................... 5 MINERAL DEPOSIT APPRAISAL ................................. 6 Tertiary-age copper deposits .............................. 6 I Granite Peak stock ................................ 7 Copper porphyry deposit possibilities .............. 7 Veinlet and disseminated deposits of copper ......... 8 I Economics ............................ 9 Skarn-hosted base-metal sulfides ................. 9 Resources ........................... 10 I Gold concentration levels in the stock ............. 10 Siliceous copper deposit ...................... 10 Other metallic mineral occurrences of probable Cretaceous/ Tertiary origin ....................................... 11 I Gold Cristle Mine ................................ 11 Montosa-Willow Canyon mercury anomaly .............. 12 Unnamed prospect (WH 105) ........................ 13 I Minerals hosted in Precambrian rock ........................ 13 Fluorite ....................................... 13 Mine subsidence ........................... 15 I Silica ........................................ 15 Tungsten ...................................... 16 Uranium ...................................... 20 I Resources ................................ 21 Miscellaneous prospects for metals ................... 23 Gypsum ........................................... 24 I Geology of the Whetstone Mountains Unit gypsum ......... 24 Gypsum resources inside the Whetstone Mountains Unit .... 25 Application and value ........................ 28 I Outcrop of the Epitaph Formation by Apache Peak .... 29 Competition from other deposits ................ 29 I CONCLUSIONS ........................................... 31 I REFERENCES ............................................. 33 I I CONTENTS--continued PaQe I ILLUSTRATIONS Fig. 1 Location map of the Whetstone Mountains Unit ............. 3 I Fig. 2 Mines and prospects of the Mine Canyon area, and outcrop area of the Granite Peak stock, with sample localities I WH77-96, WH98-102 ............................ 44 Fig. 3 Mine Canyon workings: Two Peaks Mine, unnamed adit WH86-87, and David Lee Mine, with sample localities I WH86-87, 90-93, 96, 98-99 ........................ 45 I Fig. 4 Mascot Mine, with sample localities WH77-81 ........... 46 Fig. 5 James, Evening Star, Chadwick, and Lone Star Mines and I prospects, with sample localities WH23-52 .............. 47 Fig. 6 Lone Star Mine, with sample locality WH52 ............. 48 Fig. 7 Ricketts Mine, and Precambrian(?) quartz dike, with sample I localities WH 18-22 ............................... 49 I Fig. 8 Ricketts Mine, with sample localities WIll 8-22 .......... pocket Fig. 9 Excavation at Chadwick Mine, and map of James Mine, with I sample localities WH29, 30 ......................... 50 Fig. 10 Eastern adit of Bluestone Mine and workings, cross sections of Windmill No. 1 Mine, with sample localities WH25-27, I WH9-10 ...................................... 51 I Fig. 11 Gold Cristle Mine, with sample localities WH53-55 ........ 52 Fig. 12 Gypsum occurrences, with sample localities WH56-69, WH71-76, and sample locality WH97 (a prospect related to I Granite Peak stock) .............................. 53 I Plate 1 Sample locality map of the Whetstone Mountains Unit ..... pocket I I .°. I III CONTENTS--continued I COMPOSITE EXPLANATIONS Explanation of symbols for report figures and plates, including: inset maps at various scales and 1:126,720- I scale plates .................................... 38 Explanation of symbols for report figures, including: I features of detailed mine maps, both surface and underground, at various scales (larger than 1:24,000) ...... 40 I TABLES I Table 1 Evaluation of quartz veins for tungsten content ........... 18 I Table 2 Evaluation of uranium mines and prospects .............. 22 Table 3 Evaluation of gypsum beds and associated rocks .......... 26 I APPENDIXES I A. Descriptions of reconnaissance rock-chip samples ......... A1 B. Assays of reconnaissance rock-chip samples by Bondar-Clegg and Co., Ltd, using the neutron activation I method ....................................... B1 C. Assays of reconnaissance rock-chip samples by I Chemex Labs, Inc., using the inductively coupled plasma method ....................................... C1 I D. I. Sampling methods; II. Sample preparation procedures (for assay); II1. PREVAL parameters and backup data for PREVAL I modeling, Whetstone Mountains Unit .................. D1 I I iv UNIT OF MEASURE ABBREVIATIONS USED IN THIS REPORT Acre(s) ac I Counts per second cps Degree o Inch(es) in. I Foot (feet) ft Mile(s) mi Ounce(s) oz (troy) I Part(s) per billion ppb Part(s) per million ppm Percent % I Pound(s) Ib (avoirdupois) Short ton(s) st (2,000 Ib) I Square mile(s) mi 2 I I II i'!i V m MINERAL APPRAISAL OF CORONADO NATIONAL FOREST, PART 11 ! WHETSTONE MOUNTAINS UNIT by Mark L. Chatman 1 ! SUMMARY U.S. Bureau of Mines personnel studied mineral resources of the Coronado National Forest to appraise the resources present and determine areas for possible future mineral exploration and development. This