3. Los Borregos / Technical facts

3. Los Borregos
/ Technical facts
Municipality of Ascensión, northern Chihuahua, México.
4,100 hectares.
279 km from Chihuahua, the state capital with 350,000 inhabitants; and 114 km SW of Ciudad Juárez
(1’321,004 inhabitants), and SSE and 62 km. from Ascensión. Closest high voltage power network is
80 km to the east, and the low voltage network 12 km to the SW.
The highest part of an extended hydrothermal system in which dense quartz stockwork and veins are present.
Disseminated mineralization as well.
Manganese associated with hematite, argentiferous galena, azurite, malachite and barite. Mn and Fe oxides are
mostly exposed within the supergene enrichment zone. Silver, lead, zinc and copper sulphides are expected to be
present at depth.
Andesitic breccia and tuff; rhyolitic tuff, subvolcanic dacitic and intrusive diorite.
Argillic, silicification over an extensive oxidized terrane.
The district has been productive since WWI and II, when average grades were 30% Mn; by 1959, 25% Mn, and
in the 70s, declining intermittent production averaged 22% Mn. Old terrains returned from 4 to 37% Mn, and 8
to 109 g/t Ag, Mo traces, and up to 11% Ba.
815,000 tons Mn-Ag
Early stage.
Semi-detailed geological surveying and geochemistry over 4,200 has.
An Oligocene-Miocene andesitic breccia and tuff; rhyolitic tuff, subvolcanic dacitic and intrusive diorite,
conform a volcanic field in which an extended en echelon N-S and NW parallel system of faults –probably
Miocene or younger– hosted 77 Mn-Ag, Ba and Fe veins.
After systematic sampling, eight prospects were documented.
Located 34 km SE of Bismark, a replacement deposit in limestone operated by Peñoles.
3. Los Borregos Project
At Los Borregos, an Oligocene-Miocene andesitic
breccia and tuff; rhyolitic tuff, subvolcanic dacitic and
intrusive diorite, conform a volcanic field in which an
extended en echelon N-S and NW parallel system
of faults –probably Miocene or younger–, hosted 77
Mn-Ag, Ba and Fe veins.
After systematic sampling, eight prospects were
documented: La Consolidada, La Verdún, La Corriente, San José, El Pino, La Pilita, Las Mulas and
El Dos-La Tercera. The area has a 7 km long per 5.5
km wide rectangular shape, enough to protect the
N-S and NW-SE vein systems.
Mineralization occurs as manganese oxides –cryptomelane, psilomelane, hollandite, pyrolusite–associated with hematite, argentiferous galena, azurite,
malachite and barite. Manganese and iron oxides are
mostly exposed within the supergene enrichment
zone and is expected that silver, lead, zinc and copper
sulphides may be present at depth. The district has
been productive since WWI and II, when average
grades were 30% Mn; by 1959, 25% Mn, and in the
70’s, a declining intermittent production averaged
22% Mn. Old dumps returned from 4 to 37% Mn,
and 8 to 109 g/t Ag, Mo traces, and up to 11% Ba.
Chihuahua state: 4,100 hectares