High-Sulphidation Epithermal Gold Target At Rio Loa Project
VANCOUVER - Fiore Gold Ltd. reported results from its on-going exploration program on the Rio Loa gold exploration project in the prolific Maricunga Belt of northern Chile. Recent work on the project has identified strong, coincident alteration, geophysical and geochemical anomalies indicative of a high-sulphidation epithermal gold-mineralizing system. The Miocene-age Maricunga Gold Belt has been the focus of renewed exploration for large epithermal systems over the past several years, and Rio Loa is particularly interesting because of its proximity to Gold Fields’ 3.8 million-ounce Salares Norte discovery, currently one of the highest-grade gold deposits in the Maricunga Belt.
Tim Warman, Fiore’s CEO said, “The results of the recent exploration program at Rio Loa show strong indications of a high-sulphidation gold system on the property. We’re seeing coincident and well-developed alteration, geophysical and pathfinder element anomalies over a strike length of several kilometres, despite much of the area being covered by a thin veneer of younger volcanic rocks. The next steps will include an initial reverse circulation drill program which is currently being planned to test the recently identified targets.”
Rio Loa is located in the northern part of the prolific Maricunga gold belt, which boasts more than 100 million-ounces (“Moz”) of gold in reserves, resources, and past production. Recent exploration success at the northern end of the Maricunga belt is highlighted by Gold Field’s Salares Norte gold-silver oxide discovery, with total resources of 3.8 Moz gold at 4.6 g/t and 43.8 Moz of silver at 53.1 g/t. Salares Norte has delivered some notable drilling results for Gold Fields including hole SNDD017 which returned 132 m at 53.2 g/t gold and 59.3 g/t silver. Fiore’s Rio Loa property is located approximately 25 km south of Salares Norte and can be accessed year-round by road. This 1,000 Ha property has seen minimal exploration and no drilling, but previous work has identified moderate to strong silica-argillic alteration and oxidized vuggy silica characteristic of high-sulphidation gold deposits. Rock chip sampling of trenches and outcrops by previous owners identified extensive strong anomalies of arsenic, antimony, lead and weak gold in trenches and outcrops. Recent sampling by Fiore personnel has confirmed the anomalous values in the trenches.
Alteration mapping using ASTER satellite imagery, subsequently confirmed by TerraSpec mineral analysis, shows an alteration pattern interpreted as a mixture of advanced argillic (alunite), iron-oxide and silicification within the property limits. The geochemical response and alteration pattern at Rio Loa is similar to the geochemical responses on other high-sulphidation deposits within the belt such as at Salares Norte and Kinross’ La Coipa mine.
Ground geophysical surveys were also conducted to help delineate possible gold mineralization and to assist in mapping structures, alteration, and lithology. Four Induced Polarization (IP) lines were surveyed previously during 2012 on behalf of the previous property owner. During late 2017, the previous IP survey was extended by six lines, and a ground magnetic survey was also conducted.
The resistivity data from the IP survey show a broad, strongly-conductive zone at depths greater than an average of about 200 m. This conductive material is interpreted as a large zone of alteration, likely argillic, that extends beyond the limits of the survey. A strong, narrow conductor centered near 507600E is probably associated with a N-S striking structure or fault zone. Several resistive features with deeper roots in the northern and central portions of the property may represent breccias or feeder zones. These correlate closely with trenching and strong geochemical anomalies and are considered high-priority targets for gold mineralization.
The chargeability data from the IP survey show anomalously-low amplitudes near the surface, suggesting that oxidation is present to depths of approximately 150 to 200 m over the central portion of the grid lines. Weak to moderate chargeability anomalies are present at depths of 150 m or more, particularly in the central portion of the grid and along the N-S structure. The strongest chargeability anomalies tend to flank the deep-rooted resistive targets. The lower chargeabilities over the resistive zones may indicate that oxidation is somewhat deeper in the resistive zones. The thin post-mineral volcanic cover in the area is moderately magnetic and appears to mask some of the deeper subtle magnetic anomalies indicative of magnetite-destructive alteration that would be expected in a high-sulphidation system. However, a relatively pronounced deep N-S magnetic low is identified in the southwest portion of the grid, coincident with the projected trend of the N-S resistivity structure.
Ground geophysical surveys were conducted in December 2017 by Argali Geofisica Chile E.I.R.L. (Argali) and consisted of Induced Polarization (“IP”) and ground magnetic surveys. The IP data were acquired with the pole-dipole array and a dipole spacing of 75 m expanded through 8 separations (n=1 to 8). Six E-W lines totaling 18.975 km were surveyed during 2017, and four lines totaling 11.85 km in 2012 for a total of 30.825 km. The line spacing was 500 m.
The ground magnetic survey was conducted on N-S lines spaced 100 m apart. Data were acquired as continuous profiles with 1 reading/second or an approximate station spacing of 0.6 to 1.5 m. A total of 130 line-kms of data were acquired.