Potrerillos 40Ar/39Ar Sample Descriptions and Locations

UTM Coordinates (approx. 26 deg.29'S Lat., 69 deg.26'W Long.)

Sample North East Elev Description
EH-4 7069312 460349 3925 Granodiorite porphyry, with fresh biotite phenocrysts, plagioclase phenocrysts altered to halloysite, from El Hueso Mine (Cerro Silica East).

EH-9 7069423 459951 3654 White porcelaineous, microcrystalline alunite in the Potrerillos Mine Fault beneath the El Hueso Mine (Cerro Silica). DDH-29 138.3-138.45 meters

EH-14 7069613 460217 3851 Coarse-grained alunite replacing plagioclase phenocrysts in granodiorite porphyry, accompanied by zunyite, woodhouseite, pyrite, rutile, and granular quartz, from El Hueso Mine (Cerro Silica North). Jarosite replaces octahedral pyrite. DDH-37 15.0-15.15 meters

EH-15 7069582 460217 3792 Au-bearing quartz veinlets with sericitized margins cutting granodiorite porphyry dike from El Hueso Mine (Cerro Silica). Sericite crystallinity 0.36 deg. two-theta full width of half maximum for the 10A X-ray peak. Jarosite replaces pyritohedral pyrite and forms veinlets cutting Au-quartz veinlets. DDH-37 81.75-82.35 meters

EH-17 7070554 457574 2983 Very weakly potassically altered quartz monzodiorite porphyry from the Cobre stock, with fresh hornblende, plagioclase, and biotite phenocrysts. Trace orthoclase veinlets, accompanied by disseminated bornite and chalcopyrite.

EH-18 7070543 457579 2983 Strongly potassically altered quartz monzodiorite porphyry from the Cobre stock, with biotitized hornblende phenocrysts, turbid pink orthoclase rimming plagioclase phenocrysts and pervading groundmass, and disseminated bornite and chalcopyrite.

EH-21 7070544 457579 2983 Strongly potassically altered quartz monzodiorite porphyry from the Cobre stock, with biotitized hornblende phenocrysts, turbid pink orthoclase rimming plagioclase phenocrysts and pervading groundmass, and disseminated bornite and chalcopyrite.

EH-23 7070886 457818 2983 Very late stage, gold-bearing tennantite-pyrite-chalcopyrite-galena-(sphalerite) -ankerite-anhydrite-quartz vein cutting quartz monzodiorite porphyry. Sericite is present as a vein-filling mineral and as a distinct selvedge to the vein. Sericite crystallinity 0.14 deg. two-theta full width of half maximum for the 10A X-ray peak. Cobre stock.

EH-25 7070850 457746 2983 Quartz monzodiorite porphyry, with thin pyrite-chalcopyrite veinlets having sericite selvedges cutting mosaic-textured quartz veins having pink orthoclase selvedges and bearing fine-grained bornite and chalcopyrite. Shreddy biotite replacing hornblende phenocrysts has been replaced by sericite in the vicinity of pyrite veinlets. Cobre stock.

EH-26 7070850 457746 2983 Molybdenite-chalcopyrite-quartz vein with no distinct alteration selvedge, cut by chalcopyrite-pyrite vein with coarse sericite selvedge. Later pyrite-(chalcopyrite) -calcite vein with sericitic selvedge cuts chalcopyrite-pyrite vein. Sericite replaces shreddy biotite in hornblende phenocryst sites. Sericite crystallinity 0.17 deg. two-theta full width of half maximum for the 10A X-ray peak. Quartz monzodiorite porphyry from the Cobre stock.

EH-27 7070845 457736 2983 Coarse-grained, phlogopitic vein-filling biotite, associated with chalcopyrite and anhydrite as vein-filling minerals and turbid, pink, microperthitic orthoclase as a selvedge completely replacing plagioclase phenocrysts and groundmass feldspar in quartz monzodiorite porphyry. Cobre stock.

EH-32 7070847 457740 2983 Coarse-grained sericite replacing phlogopitic vein biotite where vein biotite is cut by pyrite-chalcopyrite veinlets. Sericite crystallinity 0.28 deg. two-theta full width of half maximum for the 10A X-ray peak. Cobre stock.

EH-33 7065140 457210 4397 Fresh granodiorite porphyry from Cerro El Hueso stock.

EH-37 7068203 458830 3400 Coarse-grained sericite replacing plagioclase phenocrysts. Sericite present as coalescing envelopes around through-going pyriteńchalcopyrite veinlets cutting granodiorite porphyry. Sericite crystallinity 0.13 deg. two-theta full width of half maximum for the 10A X-ray peak. Gonzalez stock. SPG-14 283-284 meters.

EH-38 7070397 460754 3844 Fresh quartz monzodiorite porphyry from Cerro Bochinche stock.

EH-39 7070454 460810 3839 Fresh quartz monzodiorite porphyry from Cerro Bochinche stock.

EH-40 7071745 457777 3118 Fresh granodiorite porphyry from Norte stock. DD-240 110-110.1 meters

EH-41 7071757 457765 3119 Weakly potassically altered granodiorite porphyry from Norte stock, with minor orthoclase veinlets and replacement of plagioclase phenocrysts and groundmass, and minor disseminated bornite and chalcopyrite. DD-240 127.6-128 meters.

EH-46 7069786 458668 3370 Weakly Au-mineralized (150 ppb Au) quartz vein cutting sericitized granodiorite porphyry. Sericite crystallinity 0.17 deg. two-theta full width of half maximum for the 10A X-ray peak. Polvorin dike.

EH-54 7069065 460054 3865 Quartz vein with sericitized envelope cutting granodiorite porphyry El Hueso Mine, (Cerro Silica South). Spatially associated with relict sulfide minerals including chalcopyrite, bornite, and molybdenite. Sericite crystallinity 0.23 deg. two-theta full width of half maximum for the 10A X-ray peak.

EH-56 7069645 460099 3810 Microcrystalline alunite vein cutting quartz veinlets in argillized granodiorite porphyry El Hueso Mine (Cerro Silica North).

EH93-12 7063690 459200 3770 Fresh tonalite porphyry from Cuesta stock.

EH93-16 7066427 461412 3612 Fresh quartz monzodiorite porphyry dike 10 meters wide N20E 63NW, cuts EH93-15 microdiorite. Microdiorite also cut by pebble dike N87E 77SE, with granodiorite clasts. From T-17 Hill.

EH93-20 7069389 460207 3760 0.2 to 2.0 micron size fraction of illite from 1-3 mm diameter white "moteada" spots in pyritic, spotted, silicified siltstone, from 3 gram/tonne ore zone in El Hueso Mine (Cerro Silica). Illite crystallinity 0.9 deg. two-theta full width of half maximum for the 10A X-ray peak.

EH93-24 7069400 460229 3760 Nodular, very fine-grained white alunite with porcelaineous texture and conchoidal fracture, encased in massive white, very fine-grained kaolinite from the basal fault in the El Hueso Mine (Cerro Silica). This fault forms the lower limit of oxidation, and is marked by abundant sooty chalcocite, covellite, and minor native sulfur coating fracture surfaces.

EH93-40 7072000 463680 3735 Fresh plagioclase-, biotite-, and hornblende-phyric dacite flow from Cerro El Buitre.

EH93-42 7072060 463550 3750 Fresh granodiorite porphyry boulder in poorly sorted breccia (lahar-like deposit) overlain by EH93-40 dacite flow from Cerro El Buitre.

EH93-54 7069637 460251 3825 Coarse-grained alunite replacing plagioclase phenocrysts in granodiorite porphyry, accompanied by pyrophyllite, zunyite, woodhouseite, pyrite, rutile, and xenomorphic quartz. Coarse-grained dickite in veinlets and irregular masses cuts alunite and replace pyrophyllite. Jarosite replaces octahedral pyrite, and jarosite veinlets cut dickite veinlets. El Hueso Mine, outside of ore zone (Cerro Silica North).

EH93-72 7069347 460225 3887 Intensely alunitized pyroclastic rock. Sample consists entirely of friable, coarse alunite. Sample is from drill core a few meters above EH93-79, which contains abundant relict pyrite enclosed in dense xenomorphic silica. Outside of ore zone. El Hueso Mine (Cerro Silica). DDH-34 12.0 meters.

Sample	North	East	Elev	Description
EH-4	7069312	460349	3925	Granodiorite porphyry, with fresh biotite phenocrysts, plagioclase phenocrysts altered to halloysite, from El Hueso Mine (Cerro Silica East).
EH-9	7069423	459951	3654	White porcelaineous, microcrystalline alunite in the Potrerillos Mine Fault beneath the El Hueso Mine (Cerro Silica). DDH-29 138.3-138.45 meters
EH-14	7069613	460217	3851	Coarse-grained alunite replacing plagioclase phenocrysts in granodiorite porphyry, accompanied by zunyite, woodhouseite, pyrite, rutile, and granular quartz, from El Hueso Mine (Cerro Silica North). Jarosite replaces octahedral pyrite. DDH-37 15.0-15.15 meters
EH-15	7069582	460217	3792	Au-bearing quartz veinlets with sericitized margins cutting granodiorite porphyry dike from El Hueso Mine (Cerro Silica). Sericite crystallinity 0.36 deg. two-theta full width of half maximum for the 10A X-ray peak. Jarosite replaces pyritohedral pyrite and forms veinlets cutting Au-quartz veinlets. DDH-37 81.75-82.35 meters
EH-17	7070554	457574	2983	Very weakly potassically altered quartz monzodiorite porphyry from the Cobre stock, with fresh hornblende, plagioclase, and biotite phenocrysts. Trace orthoclase veinlets, accompanied by disseminated bornite and chalcopyrite.
EH-18	7070543	457579	2983	Strongly potassically altered quartz monzodiorite porphyry from the Cobre stock, with biotitized hornblende phenocrysts, turbid pink orthoclase rimming plagioclase phenocrysts and pervading groundmass, and disseminated bornite and chalcopyrite.
EH-21	7070544	457579	2983	Strongly potassically altered quartz monzodiorite porphyry from the Cobre stock, with biotitized hornblende phenocrysts, turbid pink orthoclase rimming plagioclase phenocrysts and pervading groundmass, and disseminated bornite and chalcopyrite.
EH-23	7070886	457818	2983	Very late stage, gold-bearing tennantite-pyrite-chalcopyrite-galena-(sphalerite) -ankerite-anhydrite-quartz vein cutting quartz monzodiorite porphyry. Sericite is present as a vein-filling mineral and as a distinct selvedge to the vein. Sericite crystallinity 0.14 deg. two-theta full width of half maximum for the 10A X-ray peak. Cobre stock.
EH-25	7070850	457746	2983	Quartz monzodiorite porphyry, with thin pyrite-chalcopyrite veinlets having sericite selvedges cutting mosaic-textured quartz veins having pink orthoclase selvedges and bearing fine-grained bornite and chalcopyrite. Shreddy biotite replacing hornblende phenocrysts has been replaced by sericite in the vicinity of pyrite veinlets. Cobre stock.
EH-26	7070850	457746	2983	Molybdenite-chalcopyrite-quartz vein with no distinct alteration selvedge, cut by chalcopyrite-pyrite vein with coarse sericite selvedge. Later pyrite-(chalcopyrite) -calcite vein with sericitic selvedge cuts chalcopyrite-pyrite vein. Sericite replaces shreddy biotite in hornblende phenocryst sites. Sericite crystallinity 0.17 deg. two-theta full width of half maximum for the 10A X-ray peak. Quartz monzodiorite porphyry from the Cobre stock.
EH-27	7070845	457736	2983	Coarse-grained, phlogopitic vein-filling biotite, associated with chalcopyrite and anhydrite as vein-filling minerals and turbid, pink, microperthitic orthoclase as a selvedge completely replacing plagioclase phenocrysts and groundmass feldspar in quartz monzodiorite porphyry. Cobre stock.
EH-32	7070847	457740	2983	Coarse-grained sericite replacing phlogopitic vein biotite where vein biotite is cut by pyrite-chalcopyrite veinlets. Sericite crystallinity 0.28 deg. two-theta full width of half maximum for the 10A X-ray peak. Cobre stock.
EH-33	7065140	457210	4397	Fresh granodiorite porphyry from Cerro El Hueso stock.
EH-37	7068203	458830	3400	Coarse-grained sericite replacing plagioclase phenocrysts. Sericite present as coalescing envelopes around through-going pyriteńchalcopyrite veinlets cutting granodiorite porphyry. Sericite crystallinity 0.13 deg. two-theta full width of half maximum for the 10A X-ray peak. Gonzalez stock. SPG-14 283-284 meters.
EH-38	7070397	460754	3844	Fresh quartz monzodiorite porphyry from Cerro Bochinche stock.
EH-39	7070454	460810	3839	Fresh quartz monzodiorite porphyry from Cerro Bochinche stock.
EH-40	7071745	457777	3118	Fresh granodiorite porphyry from Norte stock. DD-240 110-110.1 meters
EH-41	7071757	457765	3119	Weakly potassically altered granodiorite porphyry from Norte stock, with minor orthoclase veinlets and replacement of plagioclase phenocrysts and groundmass, and minor disseminated bornite and chalcopyrite. DD-240 127.6-128 meters.
EH-46	7069786	458668	3370	Weakly Au-mineralized (150 ppb Au) quartz vein cutting sericitized granodiorite porphyry. Sericite crystallinity 0.17 deg. two-theta full width of half maximum for the 10A X-ray peak. Polvorin dike.
EH-54	7069065	460054	3865	Quartz vein with sericitized envelope cutting granodiorite porphyry El Hueso Mine, (Cerro Silica South). Spatially associated with relict sulfide minerals including chalcopyrite, bornite, and molybdenite. Sericite crystallinity 0.23 deg. two-theta full width of half maximum for the 10A X-ray peak.
EH-56	7069645	460099	3810	Microcrystalline alunite vein cutting quartz veinlets in argillized granodiorite porphyry El Hueso Mine (Cerro Silica North).
EH93-12	7063690	459200	3770	Fresh tonalite porphyry from Cuesta stock.
EH93-16	7066427	461412	3612	Fresh quartz monzodiorite porphyry dike 10 meters wide N20E 63NW, cuts EH93-15 microdiorite. Microdiorite also cut by pebble dike N87E 77SE, with granodiorite clasts. From T-17 Hill.
EH93-20	7069389	460207	3760	0.2 to 2.0 micron size fraction of illite from 1-3 mm diameter white "moteada" spots in pyritic, spotted, silicified siltstone, from 3 gram/tonne ore zone in El Hueso Mine (Cerro Silica). Illite crystallinity 0.9 deg. two-theta full width of half maximum for the 10A X-ray peak.
EH93-24	7069400	460229	3760	Nodular, very fine-grained white alunite with porcelaineous texture and conchoidal fracture, encased in massive white, very fine-grained kaolinite from the basal fault in the El Hueso Mine (Cerro Silica). This fault forms the lower limit of oxidation, and is marked by abundant sooty chalcocite, covellite, and minor native sulfur coating fracture surfaces.
EH93-40	7072000	463680	3735	Fresh plagioclase-, biotite-, and hornblende-phyric dacite flow from Cerro El Buitre.
EH93-42	7072060	463550	3750	Fresh granodiorite porphyry boulder in poorly sorted breccia (lahar-like deposit) overlain by EH93-40 dacite flow from Cerro El Buitre.
EH93-54	7069637	460251	3825	Coarse-grained alunite replacing plagioclase phenocrysts in granodiorite porphyry, accompanied by pyrophyllite, zunyite, woodhouseite, pyrite, rutile, and xenomorphic quartz. Coarse-grained dickite in veinlets and irregular masses cuts alunite and replace pyrophyllite. Jarosite replaces octahedral pyrite, and jarosite veinlets cut dickite veinlets. El Hueso Mine, outside of ore zone (Cerro Silica North).
EH93-72	7069347	460225	3887	Intensely alunitized pyroclastic rock. Sample consists entirely of friable, coarse alunite. Sample is from drill core a few meters above EH93-79, which contains abundant relict pyrite enclosed in dense xenomorphic silica. Outside of ore zone. El Hueso Mine (Cerro Silica). DDH-34 12.0 meters.