As of June 10th over 70% of the aerial survey work has now been completed, with the remaining lines expected to be completed by the end of June. Initial results from the program are helping to define the structural controls on the mineralization. The data is currently provisional and final processing will be completed by September.
An initial phase of drilling has commenced on targets that have been identified from mapping and earlier ground geophysical programs. Geotechreserves do Brasil have been engaged to undertake a 2000 meter diamond drilling program, using a modern track-mounted Boart Longyear LF90D rig. The program is commencing in the Jaburi plant area and will test at least eight initial prospects in the broader district.
Exploration is a methodical process requiring patience. A regional mapping and sampling program was first undertaken to develop a broad understanding of the basement geology and structural trends. Many areas were found to have limited exposure, and geophysical techniques were identified as a key method to evaluate the mineral potential of the district. Ground geophysics trials were initiated to confirm the signature of the mineralization using a variety of methods including magnetic, gravity, and electrical exploration techniques. The aerial electromagnetic-magnetic survey that is currently in progress will provide an important project-scale data set. Anomalies will be prioritized for field evaluation (mapping / ground geophysics / trenching). Favourable targets will then be prioritized for subsequent exploration drill testing. Resource definition drilling will follow on prospects where significant results are returned.
Given the considerable size of the tenement at 104,000 hectares, it will take time to gain a realistic appraisal of the resource potential. However once a sufficient quantity and quality of manganese ore is discovered, a mine plan will be developed. Distance from the processing plant, site access, resource size and metallurgy are among the many factors that will have to be considered.
At all drill sites, access arrangements are negotiated with the landowner and farm manager. Measures are taken to ensure that all livestock are isolated from the drill area. The drill site is usually just large enough to accommodate the drill rig, two support vehicles and a sump. Exploration drill hole diameters range from two to four inches. Once drilling is completed the drill hole is capped and the position is recorded. The sump which was used to store water during the drilling process is backfilled. The drill site area is then restored to its original pasture condition.
Before any mining can begin, a full environmental audit of the potential site is completed. Strict environmental and mining laws ensure compliance through permitting and onsite visits by regulatory agencies. In addition, BMC has implemented its own environmental procedures aimed at ensuring its mining activities meet high standards.
Any mining or exploration fieldwork is followed by a rehabilitation program while a rigorous testing and evaluation model, run by a specialist environmental manager, assists BMC in developing innovative and practical methods for managing land affected by mining activities.
A Teamwork-Driven Program
The increased levels of exploration activity have encouraged Ferrometals Investment Manager and Senior Geologist Ganesh Bhat to return to Espigão and get a first hand understanding of the work the onsite exploration team have achieved.
“The preliminary analysis of data from ground work and the aerial survey indicates that our original geological theory concerning the formation of manganese ore by hydrothermal processes with structural controls is correct. I’m particularly interested in working with the team as they begin our drilling program to see the quantity and quality of the subsurface mineralization.”
In addition to the main exploration program, preproduction teams are trenching permitted colluvial sites to assess the extent of near-surface mineralization. Sites are prioritized for processing based on the results of these programs. Production teams are working to increase plant throughput, and are currently evaluating potential options to upgrade and expand the capacity of these plants.
With plant capacity upgrades and a developing mine plan, BMC is in a position to maintain its exploration program, while also increasing production of its high-grade, high-purity ore for sale to agricultural markets within Brazil.
General Manager of BMC Mike Bennett summarised the program. “It has taken some time to build a skilled, multidisciplinary team. Fortunately we have now found the right people, and are now benefiting from a coordinated approach from the exploration, preproduction and production teams. We have a solid foundation to evaluate the potential of the district and capitalize on opportunities that our programs reveal”.
Press Release – May 2015
Aerial surveys have begun
Helicopter surveys of BMC mining tenement has begun. Over the next two months large amounts of data will be processed to give our geology team a better understanding of the location of potential manganese sites within the tenement.
The aerial survey is planned to cross our tenements with long traverses spaced 100m apart, however weather conditions could complicate this linear approach resulting in the helicopter moving in a more random fashion. BMC have made every effort to minimise disturbances and will continue to work closely with all stakeholders within the flight path area, to ensure these surveys have a minimal impact.
Aerial survey update as in 10 Oct press release
BMC is currently moving ahead with exploration programs including aerial geophysics.
Geophysical crews are mobilizing to commence ground surveys this month. The surveys will include a variety of techniques, including induced polarization, ground magnetics and gravity. Prospective target sites for the first phase of survey include areas where manganese vein zones up to 1-3m thick have been observed. The exposure of the veins along strike is intermittent due to the presence of a shallow cover of soil and colluvium. The geophysics program will provide an improved understanding of the depth and strike extensions of thicker vein zones for subsequent drill targeting.
In addition to ground geophysics, BMC has awarded a tender for an aerial geophysics survey. The aerial survey will provide a detailed, project-scale dataset at 100m line spacings. Magnetic and electromagnetic data is gathered, and analysed to fast-track the definition of exploration targets across the region. Permit applications for the aerial program lodged with the Brazilian Minister of Defence will confirm final scheduling of flights.
Exploration from both ground and aerial geophysics will assist in defining extensions to the boulder fields that supply current mining operations and target primary manganese vein structures at depth.
Aerial Survey planned
The Aerial survey program currently surveys a broad area of tenements. Analysis of this data will allow the selection of sites for more detailed ground examination. Permit applications for the aerial program lodged with the Brazilian Minister of Defence will confirm final scheduling of flights.
What is Aerial Geophysics?
An aerial geophysics program assists in targeting concealed manganese mineralisation. This involves a helicopter magnetic – electromagnetic survey. At different stages, a fixed-wing aircraft may alternatively be used for collecting geophysics data or aerial photography.
The planned helicopter survey will involve flight traverses at low elevation along lines spaced ~100m apart. The helicopter would tow a loop of wire and geophysical instrumentation to collect data. The helicopter itself might fly ~80m above the ground (or above any obstacles such as tree canopy, towers and power lines, or buildings). The instrumentation would towed with a clearance of ~35-65m. Survey height may vary depending upon the pilot’s judgment of safe flying conditions – with greater clearances potentially around man-made structures or in rugged terrain. A fixed wing survey would fly at greater elevations, as the aircraft has less capability to adjust its clearance over hilly terrain.
Livestock may move in response to the noise of an aircraft overhead, but the aircraft will pass quickly and will not spend a long time over any given area as the survey progresses. There is no health hazard to people or livestock from the survey techniques.