Lukkacha Project

2017 05 03 Lukkacha Drobeck PHY 44a preview

 

Porphyry Copper Model

Cross Section

Lukkacha has only been recently identified as a potential porphyry copper exploration target. Prior to Miramont’s option-to-acquire only regional scale mapping and sampling had been completed.

Miramont has, since acquiring the option, now completed a reconnaissance mapping program over the entire concession area and has completed detailed mapping and geochemical sampling over a four square kilometer area. This has resulted in the definition of preliminary drill targets that will be further refined by future geophysical surveys.

Detailed Map Area

Regional

The property is underlain by volcanic rocks of the Toquepala Formation. These rocks represent a late Cretaceous to Paleogene (100 to 53 million years ago) volcanic arc. This volcanic sequence has been intruded by a complex system of quartz diorite, dacite, monzonite and granodiorite stocks and dikes (Supergroup Yarabamba of Paleocene age or possibly a younger intrusive event). The location of these intrusions are controlled by the Incapuquio regional fault which follows the NW Andean trend. All of these described units were subsequently covered by continental sediments and volcanic tuffs of the Moquegua Formation and volcanics ash and flows of the Huaylillas Formation. Copper mineralization in this belt is largely hosted by porphyry-style deposits formed within the Yarabamba Supergroup. A younger porphyry, Chipispaya, only 10 km from Lukkacha is reportedly associated with an intrusion of Miocene age (23 million years) and possibly defines a new sub-belt of mineralization adjacent to the principal copper belt.

Project Geology

           Lithology

The principal area of interest covers four square kilometers within the concession block. Detailed geologic mapping here has defined an area of a complex igneous and hydrothermal activity with key characteristics of a copper porphyry deposit.

The principal intrusive phase is a quartz-monzonite which is highly altered by hydrothermal solutions. Microscopic thin-sections show a clear porphyritic texture.

The quartz monzonite is cut by a series of small intrusive bodies, dikes and sills of plagioclase-hornblende porphyry. The porphyry texture is clear in both hand specimens and thin-sections. Taken together these later intrusions show an elongate E-W trend with NE displacement along pre-existing faults.

Subsequently three different breccia phases formed and cut pre-existing intrusive rocks:

  • Tourmaline Breccia - this breccia is formed of clasts from prior intrusive phases within a black tourmaline and silica matrix. It forms extensive areas found principally in the central and south eastern sectors of the map area. The tourmaline is thought to represent a latter, volatile-rich phase related to copper porphyry mineralization-it is found extensively in nearby copper deposits.
  • Silica Breccia - this is a clast-supported breccia in a siliceous matrix. It generally form small bodies. The largest is approximately 200 x 400 meters in the southern sector of the map area.
  • Crackle Breccia - this is usually found adjacent to the silica breccia and may represent a gradation of the silica breccia. It too is clast-supported with a predominantly silica matrix.

           Structure

The principal controlling structure is the regional NW-trending Incapuquio fault which also controlled the emplacement of other major copper deposits in the region. The quartz-monzonite intrusion is emplaced between the Incapuquio and the parallel Molleraco faults. Second order tensional faulting forms in an ENE to E-W direction. Veinlets, breccias and other evidence of hydrothermal activity follow this latter fracture set.

          Alteration

Rock alteration typical of porphyry deposits covers the entire mapped area and in total extends over 2.5 x 6 km. Within the central mapped area three principal alteration types have been found and fit the well-defined pattern of typical porphyry deposits.

  • Propylitic - This is identified by the presence of chlorite, epidote and sericite in varying proportions. It is generally found at higher elevations or further away from the central zone of interest.
  • Phyllic - This is known by the presence of quartz and sericite. It is found at lower elevations and more extensively in the south-east sector. It appears to have formed below the propylitic halo. In areas this alteration is found with tourmaline disseminations or veinlets.
  • Silica - This is generally found forming the matrix of the various breccia units. The presence of the mineral pyrophyllite in the Southeast sector may indicate the bottom of a lithocap formed over a porphyry system.

          Mineralization

Mineralization in the mapped area is composed of iron-oxides (hematite, goethite and jarosite) that are typical of a leached zone in a copper porphyry system. Copper and molybdenum oxide have also been found at one locale. Pyrite is found with both phyllic and propylitic alteration.

Mineralization is found primarily as patinas on fractures and in veinlets. Jarosite and goethite are found along the borders of the system and at higher elevations while hematite (w/ goethite) is found more centrally and lower down.

Veins and veinlets are found throughout the mapped area and in both the quartz-monzonite and plagioclase-hornblende porphyry bodies. The veinlet emplacement is controlled by fracturing and the formation of sheeted veins in certain areas.

          Geochemistry

Almost 400 geochemical samples were collected at approximately 100 meter centers. Copper shows a clearly defined anomaly within the central zone. It covers an area of 450 by 1000 meters, elongate in an E-W direction and centered in an area coincident with tourmaline breccia and complex alteration. Copper values up to 800 ppm Cu have been found - values are considered anomalous for a leached cap environment .

A smaller molybdenum anomaly in the same area has been defined by values greater than 20ppm Mo.

Geologic Map

Photo of Tourmaline Breccia 1

Alteration Map

2017 05 03 Lukkacha Drobeck PHY 44a preview

Mineralization Map

IMG 3594

Copper Geochemistry