BAUXITES
I Stage — preparation:
Composing a geological map with the scale а 1:50 000 — 1:100 000 for all previously explored areas as well as areas with promising geological and geomorphological properties.
- in case of the lack of topobase – composing functional topographical map using old French maps with the scale 1:200 000, Soviet Genshtab (military) maps (1:200 000), orbital imagery and aerial imagery
Composing geomorphological maps to define a more detailed contour of the plateau within which exploration and estimation of bauxite objects will be conducted
Composing a general program of exploration of bauxite-rich objects based on map analysis and existing data about previously explored objects
Composing a work program for each year covering the following:
– General information about regions of interest
– Rationalization of types and volumes of work
– The methodology of conducting each type of work
– Schedule of operations and their costs
Composing topographic maps with the scale 1:20 000 – 1:30 000 for each bauxite plateau
II Stage – Exploration and estimation across the whole territory of the client (net 600 х 600 and/or 300 х 300)
These operations are conducted in the following order:
- Establishing a field camp
- Installing surveying benchmarks, 2 — 4 for each plateau using high-accuracy GPS
- Building roads and platforms on the plateau using bulldozers
- Positioning points for future drilling according to the approved network using portable GPS
- Auger drilling with sampling each meter and creating short (unified) description of the cut
- Core drilling to control auger drilling and analyzing the geological structure of the bauxite-carrying thicker (5% — 10% of the bores created by auger drilling)
- Delivering the samples to the main base
- Laboratory refinement of samples (sun drying in the closed hangar, reduction, crushing in light jaw crushers, drying in kilns under 105 °С, abrasion on disk erasers under 150 micron) and preparing samples for shipment as well as storing duplicates
- During field work, most roads created by bulldozers are used to form geological routes for geological and geomorphological mapping
- Based on results of field research and after receiving the results of analysis of all samples, all the necessary maps and plans are composed for each area and for the whole territory, a multivariant estimation for bauxites is also prepared. A report on the results of geological works highlighting promising objects and recommendations for future exploration is created.
III Stage — preemptive surveillance (net 150x150)
The works are conducted on the best plateau chosen based on the results of the exploratory and estimative operations and approved by the client.
The works are conducted in the following order:
- Composing the work program and receiving the approval from the client
- Building roads and platforms on the plateau using bulldozers
- Instrumental breakdown of the profiles and fixating points for future drilling
- Auger drilling with sampling each meter and creating short (unified) description of the cut
- Core drilling to control auger drilling and analyzing the geological structure of the bauxite-carrying thicker (5% — 10% of the bores created by auger drilling)
- Topographical binding of drilled wells using high-accuracy GPS or tacheometer
- Delivering the samples to the main base
- Laboratory refinement of samples (sun drying in the closed hangar, reduction, crushing in light jaw crushers, drying in kilns under 105 °С, abrasion on disk erasers under 150 micron) and preparing samples for shipment as well as storing duplicates
- During field work, most roads created by bulldozers are used to form geological routes for geological and geomorphological mapping
- Based on results of field research and after receiving the results of analysis of all samples, all the necessary maps and plans are composed for each area and for the whole territory, a multivariant estimation for bauxites is also prepared. A report on the results of geological works highlighting promising objects and recommendations for future exploration is created.
IV Stage – Detailed surveillance (net 75 х 75):
These works are conducted on 1—3 deposits defined as prioritized objects for development and mining.
- After the work program is composed and approved, special works and research are added to the list of standard operations:
- Systematic hydrogeological observations;
- Geological sampling to determine mechanical and physical characteristics (volumetric mass, loosening coefficient, filtration coefficient, etc.) of bauxites and relative formations (overburden and interburden);
- Studying and analyzing the composition of bauxites and technological (metallurgical) properties based on the standard laboratory leaching test.
- Based on the results of the works, a report with all the necessary for development and mining information is created.