Overview
Stage | Residual leach |
Mine Type | Open Pit |
Commodities |
|
Mining Method |
|
Processing |
- Heap leach
- Carbon in column (CIC)
- Carbon adsorption-desorption-recovery (ADR)
- Solvent Extraction & Electrowinning
- Cyanide (reagent)
|
Mine Life | 7.5 years (as of Jan 1, 2018) |
Mining was suspended at Mineral Ridge in early November 2017. On January 4, 2018, the Company announced an updated feasibility study outlining positive economics for processing the residual heap leach material and mining of higher-grade mineralization in the existing pits. The study provides ~7.5 years of additional mine life at Mineral Ridge and 250,500 oz. life of project gold sold at a total cash cost of US$805/oz. The Company is pursuing financing for the construction of a 4,000 TPD milling facility with CIL recovery and dry stack tailings circuit. |
Latest News | Scorpio Gold Receives Permit to Advance Mining, Processing & Exploration Activities at its 100% owned Mineral Ridge Operation, Nevada June 24, 2019 |
Source:
p. 1
Company | Interest | Ownership |
Scorpio Gold Corp.
|
100 %
|
Indirect
|
Mineral Ridge Gold, LLC
(operator)
|
100 %
|
Direct
|
Summary:
The Mineral Ridge gold deposits occur on the northeast flank of the Silver Peak range of the Silver Peak mining district. The mining district occurs along the Walker Lane structural corridor, a structurally complex region, with the Sierra Batholith to the west and the Basin and Range Province to the east. Within the corridor, Precambrian through Cenozoic age metamorphic, intrusive and sedimentary rocks occur that have been subjected to folding and thrust faulting, low angle extensional deformation, and high-angle faulting.
The precious metal deposits at Mineral Ridge consist of structurally controlled gold mineralization hosted by the lowermost unit of the Wyman Formation. The gold mineralization is invariably associated with quartz impregnations either as:
• Quartz veins and veinlets/stringers in alaskite
• Quartz veins and veinlets/stringers in Wyman Formation limestone
• Quartz veins ranging from about one foot to over 15 ft
Dilation resulting from multiple periods of dip-slip movement along a series of braided extensional faults created the conduits for the multi-stage emplacement of quartz and the attendant gold mineralization. In this sense, the Mineral Ridge deposits are considered to be detachment fault hosted.
The gold bearing quartz impregnations were emplaced along low-angle or bedding plane extensional faults developed in the limestone and alaskite rocks. There are two or more phases of quartz injection but it is apparent that only one phase is associated with the gold mineralization.
Gold is present as native gold and electrum that occurs as irregular shaped intergrowths in quartz associated with interstitial space and small fractures. Gold also occurs as irregularly shaped intergrowths and as fracture fillings associated with goethite, much of which was derived from original pyrite. In partially oxidized mineralization, gold occurs with both pyrite and goethite. Gold particle size varies from 1 to 2 microns to about 700 microns, but most of the particles are in the 5 to 50 micron size range, and should not lead to a significant particle nugget effect problem. Gold to silver ratios are typically in the 2:1 range. Because of the small gold particle size and intergrowths with quartz, extensive crushing is needed to allow for the effective cyanide heap leaching of the gold. Locally, minor amounts of galena, sphalerite and anglesite/cerrusite have been observed in the mineralization.
The gold mineralization at Mineral Ridge is primarily associated with milky quartz veins and lenses accompanied by local argillization and some sericitization. The individual zones can be as much as 50 ft thick, typically consisting of a higher grade quartz veins from five to 30 ft thick, surrounded by a lower grade envelope of mineralization. Two or more high grade zones are commonly observed stacked in en echelon patterns. Gold deposition is structurally controlled, and some of the highest grade mineralization is found in shoots that are at an oblique angle to the direction of movement of extension.
Gold is present as native gold and electrum that occurs as irregular shaped intergrowths in quartz associated with interstitial space and small fractures. Gold also occurs as irregularly shaped intergrowths and as fracture fillings associated with goethite, much of which was derived from original pyrite. In partially oxidized mineralization, gold occurs with both pyrite and goethite. Gold particle size varies from 1 to 2 microns to about 700 microns, but most of the particles are in the 5 to 50 micron size range, and should not lead to a significant particle nugget effect problem. Gold to silver ratios are typically in the 2:1 range. Because of the small gold particle size and intergrowths with quartz, extensive crushing is needed to allow for the effective cyanide heap leaching of the gold. Locally, minor amounts of galena, sphalerite and anglesite/cerrusite have been observed in the mineralization.
Gold deposits on the Mineral Ridge Property are hosted within a structural envelope in the lower unit of the Wyman Formation near its contact with the crystalline core rocks. Quartz and felsic intrusive boundaries are common in this structural zone. These boundaries are elongate within, and sub-parallel to the direction of extension as a whole and are exposed in outcrop and in the underground workings. Elongate, braided, ductile shear zones surround the boundaries, with these shear zones being preferentially in-filled by milky quartz veining associated with mineralization and the better gold grades. This zone of ductile shearing comprises the structural mineralized envelope, and is internal, and sub-parallel to the limits of the structural slab. Internal to the mineralized envelope, other, smaller-scale fault and fold sets occur, which correspond to higher grade mineralized shoots. Based on mapping of the historical underground stopes within the Mary and Drinkwater deposits, some of the high grade shoots historically exploited by underground methods were localized at the inflection point of small flexures where dilation zones were formed when the limb of the fold steepened. These shoots lie at an angle of 38° to 45° from the horizontal, versus the average 25° angle of the structural zone. It is believed that the highest-grade mineralized shoots are related to a second, perpendicular set of flexures accompanied by normal faulting that intersect the dilation zones.
Summary:
The mineral deposits at the Project are being mined by conventional open pit mining methods. A mining contractor is being utilized to perform all mining functions including: blasthole drilling, blasting, loading and hauling, as well as road and pit maintenance functions.
The Mary pit is the largest of the pits with an overall strip ratio of 8.3:1 (waste:ore). Access to the Mary pit is via the existing ramp system. A new access is being developed by dumping waste material to the southeast of the final pit limits at a gradient of 10%. This new ramp will access the lower benches of the pit and is expected to be completed in the third quarter of 2014. With the exception of the last three benches accessed via a 40 ft single lane ramp, ramp widths are designed at 80 ft. The pit was designed to use 10 foot single bench with up to six benches mined before leaving a 22 ft catch bench. This corresponds to the mineral resource model block height. The benching system varies within the pit due to the access ramp and pit slope constraints. The final pit design utilizes a spiral ramp system to maintain a uniform ingress and egress for the pit. Mining in the Drinkwater pit will be completed in August of 2014. The remaining strip ratio in the Drinkwater pit is 1.9:1 (waste:ore). Access to this pit is via a haul ramp which utilizes switchbacks to maintain the road system on the south side or footwall of the Drinkwater pit. As the physical size of the two pits is relatively small, each pit is mined and scheduled as a single phase.
The satellite pits (Bluelite, Solberry, Brodie, and Wedge) are all relatively small pits. The satellite pits have an overall strip ratio of 7.4:1 (waste:ore). Access to the pits is developed using a spiral ramp system or a slot cut (Brodie pit) where appropriate. Access to each of the Satellite pits is via 50 foot single lane ramps with pullouts designed to allow the use of 100-ton haul trucks.
Processing
- Heap leach
- Carbon in column (CIC)
- Carbon adsorption-desorption-recovery (ADR)
- Solvent Extraction & Electrowinning
- Cyanide (reagent)
Flow Sheet:
Summary:
MRG processes ore at Mineral Ridge with multi-stage crushing (four stages) that produces an 80% minus 6 mesh material that is agglomerated with cement and stacked on a heap leach pad. The ore is leached at a solution application rate of 0.0025 to 0.0040 gpm/ ft² of heap surface. Solution passing through the stacked ore on the heap leach is discharged out the base of the pad via 10” perforated HDPE lines. These 10 inch lines discharge into the HDPE double lined pregnant pond which is then pumped into the ADR plant where the solution is contacted with activated carbon in a five cell vertical column Carbon-in-Column (CIC) system for recoveries of the precious metals contained. The solution exits the column reporting to a HDPE double lined barren pond. A pump system then pumps the solution back onto the heap leach pad for further leaching. The carbon is loaded to approximately 100 oz/ton gold and is removed from the column and sent to Kimberley, Idaho for custom stripping by Metals Researc ........

Recoveries & Grades:
Commodity | Parameter | 2019 | 2017 | 2016 | 2015 | 2014 | 2013 |
Gold
|
Recovery Rate, %
| ......  | | ......  | ......  | ......  | |
Silver
|
Recovery Rate, %
| ......  | | ......  | ......  | ......  | |
Gold
|
Head Grade, g/t
| | 1.57 | 1.44 | 1.52 | 1.72 | 2.32 |
- Subscription is required.
Production:
Commodity | Units | 2019 | 2018 | 2017 | 2016 | 2015 | 2014 |
Gold
|
oz
| ......  | ......  | 19,045 | 36,879 | 39,690 | 40,814 |
Silver
|
oz
| ......  | ......  | ......  | ......  | ......  | ......  |
All production numbers are expressed as metal in doré.
- Subscription is required.
Operational Metrics:
Metrics | 2017 | 2016 | 2015 | 2014 | 2013 |
Total tonnes mined
| ......  | 5,104,882 t | 7,764,789 t | 6,485,523 t | 5,195,374 t |
Ore tonnes mined
| ......  | 750,204 t | 984,850 t | 919,577 t | 893,223 t |
Waste
| ......  | 4,354,678 t | 6,779,939 t | 5,565,946 t | 4,302,151 t |
Daily mining rate
| ......  | 18,167 t | 23,901 t | | |
Tonnes processed
| ......  | 846,140 t | 891,997 t | 974,346 t | 903,337 t |
Stripping / waste ratio
| ......  | 5.4 | | | |
Reserves at January 2, 2018:
Category | OreType | Tonnage | Commodity | Grade | Contained Metal |
Proven
|
In-Situ (OP)
|
2,474 k tons
|
Gold
|
0.047 oz/ton
|
116.2 koz
|
Probable
|
In-Situ (OP)
|
1,239 k tons
|
Gold
|
0.032 oz/ton
|
40.1 koz
|
Proven & Probable
|
In-Situ (OP)
|
3,713 k tons
|
Gold
|
0.042 oz/ton
|
156.3 koz
|
Proven & Probable
|
Leach Pad
|
6,855 k tons
|
Gold
|
0.017 oz/ton
|
117.2 koz
|
Proven & Probable
|
Leach Pad
|
6,855 k tons
|
Silver
|
0.017 oz/ton
|
115.9 koz
|
Measured
|
In-Situ (OP)
|
2,088 k tons
|
Gold
|
0.074 oz/ton
|
155.2 koz
|
Measured
|
Leach Pad
|
2,895 k tons
|
Gold
|
0.017 oz/ton
|
48.5 koz
|
Measured
|
Leach Pad
|
2,895 k tons
|
Silver
|
0.016 oz/ton
|
46.4 koz
|
Indicated
|
In-Situ (OP)
|
1,095 k tons
|
Gold
|
0.066 oz/ton
|
72.6 koz
|
Indicated
|
Leach Pad
|
4,220 k tons
|
Gold
|
0.017 oz/ton
|
73.2 koz
|
Indicated
|
Leach Pad
|
4,220 k tons
|
Silver
|
0.018 oz/ton
|
74.1 koz
|
Measured & Indicated
|
In-Situ (OP)
|
3,183 k tons
|
Gold
|
0.072 oz/ton
|
227.8 koz
|
Measured & Indicated
|
Leach Pad
|
7,117 k tons
|
Gold
|
0.017 oz/ton
|
121.7 koz
|
Measured & Indicated
|
Leach Pad
|
7,117 k tons
|
Silver
|
0.017 oz/ton
|
120.4 koz
|
Inferred
|
In-Situ (OP)
|
182.9 k tons
|
Gold
|
0.059 oz/ton
|
10.73 koz
|
Inferred
|
Leach Pad
|
76 k tons
|
Gold
|
0.016 oz/ton
|
1.2 koz
|
Inferred
|
Leach Pad
|
76 k tons
|
Silver
|
0.027 oz/ton
|
2 koz
|
Heavy Mobile Equipment as of January 2, 2018:
HME Type | Quantity |
Backhoe
|
1
|
Grader
|
1
|
Rockbreaker
|
1
|
Truck (dump)
|
1
|
Mine Management:
Job Title | Name | Profile | Ref. Date |
.......................
|
.......................
|
|
May 2, 2020
|
- Subscription is required.
Corporate Filings & Presentations:
- Subscription is required.
News:
Aerial view:
- Subscription is required.