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    Steppe Gold Limited © 2025 All Rights Reserved.
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    7. Boroo & Ulaanbulag Mine

    Boroo & Ulaanbulag Mine

    Quick Facts
    Ownership:100%
    Location:Selenge Province, Mongolia
    Status:Operating
    Operation: Open-Pit Mine
    Commodity:Gold
    Location
    View map
    Boroo Gold is located 140 km northwest of the capital city, Ulaanbaatar.
    The Boroo Gold operations, owned by Boroo Gold LLC, a subsidiary of Steppe Gold Ltd., comprise hard-rock and placer deposits located in Selenge and Tuv provinces of Mongolia, covering approximately 6,594 hectares. The portfolio includes the producing Boroo deposit, the Ulaanbulag deposit, and the Bor Nuur exploration license, forming a consolidated asset base across the project area.

    The Boroo site includes an open-pit mine, processing plant, and tailings storage facility, with mining at both Boroo and Ulaanbulag carried out using conventional open-pit methods. Ore is processed through leach/CIP and gravity concentration for gold recovery.

    The operation is supported by a production schedule based on an annualized mill feed rate of 5,000 tonnes per day and total mining capacity of approximately 50,000 tonnes per day.

    Operating since 2003 and achieving commercial production in March 2004, the projects contain mineral reserves expected to support operations through 2031 and are supported by well-established infrastructure for ongoing open-pit mining activities.

    Combined Land Package

    6,594 Ha
    Quick Facts
    Ownership:100%
    Location:Tuv Province, Mongolia
    Status:Operating
    Operation: Open-Pit Mine
    Commodity:Gold
    Location
    View map
    Ulaanbulag Mine is located 19 km southeast of the Boroo Mine complex.
    The Ulaanbulag Mine is a satellite deposit located near the Boroo Mine. Both projects share key infrastructure, including the mining fleet, processing facilities, and the CIL plant. Their combined significant mineral reserves are expected to support operations until 2031.

    Combined Land Package

    6,594 Ha

    Geology

    Mineralization

    Reserves & Resources

    Mining and Processing

    Gallery
    Boroo-Gallrey-6
    Boroo-Gallrey-5
    Boroo-Gallrey-3
    Boroo-Gallrey-4
    Technical Report

    NI 43-101 Technical report

    View more

    Geology

    The geology of the Boroo area is dominated by the folded Haraa sediments, (PZhr), a fairly monotonous sequence of flysch sediments consisting of siltstone, sandstone and greywacke. These rocks are of regional extent and are interpreted to be of Lower Paleozoic age. Intrusive rocks of the Boroo Complex, of early Paleozoic age (~520 Ma to 450 Ma), have intruded the sediments. In the area, the Boroo complex is represented by leucocratic granite and granodiorite (PZgr), underlying the eastern part of the property.

    Detailed drilling around the Boroo gold deposits shows that the contact between the intrusive and the sedimentary rocks is highly irregular, with sedimentary xenoliths floating in the intrusive rocks in the border zone. A significantly younger igneous event of probably late Paleozoic age is restricted to narrow vertical and shallow dipping dikes and fissures of granitic to dioritic composition.

    The fault pattern, with the exception of the gold-bearing structures, is poorly known, but two crossing, high-angle, faults are indicated, one of them striking 70°, the other 340°, parallel to the Highway Fault mentioned above.  The trace of the 340° fault, in its northern part, is directly underneath the Ikh Dashir Placer.  A parallel fault is indicated on the satellite picture approximately 1.7 km to the east.

    Mineralization

    The bulk mineable gold mineralization at Boroo is hosted in a strongly quartz–sericite altered and sulfidized nearly flat lying zone controlled by the Boroo fault. The fault has been traced for a distance of 2.4 km and is thought to be a thrust fault that dips at an angle of 10° to the north-west and trending north-east (see Figure 7-2). It cuts across the intrusive contact between sediments and granitic rocks in the north but is entirely contained within the sediments in the south.

    Two main types of mineralization have been noted:

    • Gold-sulphide zones host the largest proportion of gold mineralization at Boroo. This type of mineralization is strongly altered quartz-sericite sulphidized zones that occur in thin, irregular veinlets, less often in breccia zones, and disseminated within the pervasive alteration. The intensity of sulphide mineralization depends on primary host rock and intensity of alteration being stronger in the granites than metasediments. The main sulphide minerals are pyrite, arsenopyrite and rarely chalcopyrite, tetrahedrite and galena. It appears that the gold in this mineralization is relatively fine grained.
    • Gold-quartz vein type. The second major gold bearing facies is massive, white quartz veins in which gold is commonly coarse-grained. The thickness of quartz veins varies from a few centimetres to up to 3 m and appears as infill veins and veinlets in fractures within mostly metasediments. Veins contain small amount of sulphides and mostly coarse-grained visible gold. This type of mineralization from a volume perspective is subordinate, however, can carry very high gold values of up to several hundred grams per tonne.

    Reserves & Resources

    Notes
    1. Boroo and Ulaanbulag Mineral Resources are as of January 1, 2024, based on the CIM Definition Standards (2014).
    2. Mineral Resources that are not Mineral Reserves have no demonstrated economic viability.
    3. Reporting cut-off grade for Boroo and Ulaanbulag Mineral Resources is 0.1 g/t Au (include both heap leach and milling ore).
    4. The Boroo and Ulaanbulag’s mineral resources has been depleted for mining up to the mining (without backfilling) as of January 1, 2024.
    5. The Mineral Resources are stated as in situ dry tonnes. All figures are in metric tonnes.
    6. Figures have been rounded to the appropriate level of precision for the reporting of Mineral Resources.
    7. Due to rounding, some columns or rows may not compute exactly as shown.

    Mining and Processing

    Boroo Gold uses conventional open-pit mining methods to extract a nominal 50,000 tonnes of material per day, supported by a mill with a processing capacity of approximately 1.8 million tonnes of ore per year (5,000 tpd). The operation employs a workforce of over 600 personnel.

    The site is connected to the central power grid, with processing facilities utilizing grid electricity.
    The existing Boroo Gold facilities include:

    • Processing plant (crushing, grinding and leaching)
    • Heap leach infrastructure
    • Tailings storage facility
    • Treatment circuits
    • Water management systems
    • Chemical and reagent storage
    • Supporting infrastructure (maintenance, warehousing and administration)

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