Overview
Stage | Construction |
Mine Type | Underground |
Commodities |
- Potash
- Salt (evaporated)
- Salt (rock)
|
Mining Method |
- Continuous
- Room-and-pillar
|
Processing |
- Crush & Screen plant
- Flotation
- Leaching plant / circuit
- Dissolving & Crystallising
- Mechanical evaporation
|
Mine Life | 30 years (as of Jan 1, 2019) |
Latest News | Highfield Granted Muga Gate Construction Licence In Spain June 24, 2022 |
Source:
p. 3
The Concession is wholly owned by and exploration is operated by Geoalcali S.L., the wholly owned Spanish subsidiary of Highfield Resources.
Summary:
The depositional basin bounds are defined to the south-west at the east-south east/west-north west trending Rocaforte Syncline near the margin of the Aragón River. To the north-west is the Sierra de Leyre anticlinal structure that overthrusts the Pamplona Marls Formation, the underlying unit of the evaporite. This thrust and two reverse faults run approximately east-west.
The first fault in the north is within the Pamplona Marls over Yesa turbidites. The second is coincident with the Liedena Sandstone, which overlays the evaporite. These faults are considered the extension of the Loiti Fault towards the east which also corresponds to the synsedimentary line between marine sediments within the Basin to the Eocene-Oligocene continental sediments at the thrust front.
The south boundary of the Exploration Target is an important fault running north-west/south-east that extends towards the east acting as limit to Magdalena anticline, considered the southern limit of southeastern section of the Muga Project area. In the west, the fault converges to the Loiti structure beyond the investigated area.
Mining Methods
- Continuous
- Room-and-pillar
Summary:
For the planned mine production panels, the tonnage and grade have been diluted by 15 cm of waste in the roof and the floor. The seams are also constrained by a minimum mining height of 2.1 metres which is consistent with the planned mining equipment. The shallow dipping seams utilise a set of two parallel roadways as the main development access, one for fresh air intake and access and the other for exhaust ventilation and conveyor belt materials handling system. The mining method approach is a typical Room and Pillar (“R&P”) panel layout. The room width is specified at 8 metres and the height and pillar size are determined by the total combined seam thickness, geotechnical constraints due to depth below surface and/or any equipment limitations.
The inclined potash seams in the north-west of the deposit require an alternative mining approach to the R&P panel layout used for the shallow dipping seams, to minimise dilution and maximise extraction, taking into consideration the geotechnical constraints and equipment limitations. For the inclined seams the planned dilution effect is considered for extraction by Continuous Miners only. It is assumed that extraction by Road Headers will have no planned dilution as the equipment is able to mine selectively to the dipping seam contact.
Underground access will be by twin parallel declines from surface, over a length of 2.6 km to a depth below surface of approximately 350 meters. The declines, approximately 25 metres apart along their length, are connected by three crosscuts and will be developed concurrently with bolter-miners using continuous haulage systems to transport mined material to surface. The same equipment will be used to develop underground infrastructure including workshops and service areas such as emergency evacuation chambers, pumping stations and electrical substations.
The primary production method will be room and pillar with an advancing chevron pattern approach. The pillar design has been assessed to provide an optimal extraction ratio while maintaining ground stability to ensure safe working and environmental conditions are achieved in the potash environment.
The mining fleet includes bolter-miners for main access development, continuous miners for high volume thick seam extraction and road headers for selective mining of thinner and steeper dipping areas.
In-seam horizontal exploratory drilling will be undertaken once the declines are completed and will continue from strategic positions throughout the mine life.
Secondary extraction is achieved through floor-cuts and pillar cross-cuts on mining retreat. Mineral haulage will be with high capacity electric shuttle cars from the face to a crusher located in the seam and then conveyed to surface. Parallel conveyor systems will be used to convey ore from working areas and separately place waste material into underground workings. The shift system enables 21 hours per day cutting time per machine.
Processing
- Crush & Screen plant
- Flotation
- Leaching plant / circuit
- Dissolving & Crystallising
- Mechanical evaporation
Flow Sheet:
Summary:
Mined potash grade and process recoveries have been assessed based upon the resource geology assessment, mine planning, metallurgical test work, and technical process studies that have been completed to date. The production of MOP at the project´s full capacity peaks at over 1.330 Mtpa with an average of 1.005 Mtpa. The 2019 Mine Plan yields an estimated mine life of 30 years comprising approximately 19 years of mine life from Muga as developed from the Muga Ore Reserves and a further 11 years from Muga Inferred Mineral Resources and the Exploration Target from the Vipasca abutting tenement. On a tonnage basis the 30 years of Muga mine life is estimated to be 109 million tonnes of Muga Proved and Probable Reserves, 22 million tonnes from Muga Inferred Mineral Resources and 49 million tonnes from the abutting Exploration Target.
The enhancements to the circuit have resulted in recovery improvements to approximately 94%, the production of commercial vacuum salt, removal of mag ........

Recoveries & Grades:
Commodity | Parameter | Avg. LOM |
Potash
|
Recovery Rate, %
| 94 |
Potash
|
Head Grade, %
| 10.7 |
Potash
|
Concentrate Grade, %
| 60 |
Projected Production:
Commodity | Product | Units | Avg. Annual | LOM |
Potash
|
MOP
|
Mt
| 1 | 30 |
Salt (evaporated)
|
Crystals
|
Mt
| | ......  |
Salt (rock)
|
De-icing salt
|
Mt
| | ......  |
Operational Metrics:
Metrics | |
Ore tonnes mined, LOM
| 179.8 Mt * |
Annual production capacity
| 1.33 Mt of MOP * |
* According to 2019 study.
Reserves at October 31, 2021:
Ore Reserves are reported at an 8% K20 cut-off which is based on potash price assumptions, metallurgical recovery assumptions from initial testwork, mining costs, processing costs, general and administrative (G&A) costs, and other factors.
Category | Tonnage | Commodity | Grade |
Proven
|
45.3 Mt
|
K2O
|
10.5 %
|
Proven
|
45.3 Mt
|
Magnesium
|
0.3 %
|
Proven
|
45.3 Mt
|
KCl
|
16.6 %
|
Probable
|
59 Mt
|
K2O
|
10 %
|
Probable
|
59 Mt
|
Magnesium
|
0.6 %
|
Probable
|
59 Mt
|
KCl
|
15.8 %
|
Proven & Probable
|
104.3 Mt
|
K2O
|
10.2 %
|
Proven & Probable
|
104.3 Mt
|
Magnesium
|
0.5 %
|
Proven & Probable
|
104.3 Mt
|
KCl
|
16.1 %
|
Commodity Production Costs:
| Commodity | Units | Average |
C1 cash costs
|
Potash
|
EUR
|
...... *†
|
Assumed price
|
Potash
|
EUR
|
...... *
|
* According to 2019 study / presentation.
† Net of By-Product.
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2019 Study Costs and Valuation Metrics :
Metrics | Units | LOM Total |
Total CapEx
|
$M EUR
|
......
|
After-tax NPV @ 8%
|
$M EUR
|
......
|
After-tax IRR, %
|
|
......
|
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Corporate Filings & Presentations:
Document | Year |
...................................
|
2021
|
...................................
|
2021
|
...................................
|
2019
|
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News:
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