- Semi strategic geochemistry exploration
- Analysis and interpretation
- Tactical geochemical prospecting
- Trenches, survey ad essay appraisal
- Evaluation of exploitable ore resources
Cheikh T. Diop Geology and Engineering was contracted to conduct all three phases of the mine development and processing plant design plan. The SGS testing will be conducted at the Bamako Mali lab. Once the test results are received, an updated version of this report will be furnished.
The NGari Seekoto and Tinkoto Sou perimeters are covered on more than 80% of their surface by laterite ironstone, a fact which makes it difficult for geological prospecting work. The ground rock Geo-chemistry is so vital to the boundaries of the known mineralized structures and the discovery of new gold anomalies on these perimeters. Geo-chemistry is a coupled recognition geological survey 1: 10 000, carried out by a geologist who is a coordinator of field work. Geo-chemical sampling began January 19, 2014 by the opening of additional access tracks to facilitate the movement on the ground and thus greatly reduce the time of operations. It was preceded by the Organization of two meetings of consultation (January 15 and 18 /2014), with the participation of those responsible for the strategy, consulting geologist, prospector geologist and the laboratory assistant. In 16 days, 517 samples of soil and laterites, were collected. SGS Analabs De Bamako laboratory came retrieve the samples on, February 2nd 2014. Mr. Lamine Sy, head of the Department of Industry and the Mines of Kedougou, conducted a tour of the perimeter of Tinkoto Sou, during the Geo-chemical sampling.
Sampling was conducted along the geochemistry profiles, spaced 100 meters apart, with sampling every 25 meters. The coordinates of the points were determined using a GPS (UTMWGS 84) and recorded in the field notes. Both types of samples were taken.
Soil or Laterites
Soil samples are systematically taken on soft soil or lateritic sites at an average depth of 20 to 40 cm depending on the hardness of the ground. Prior to sampling, the superficial part, often moist, is etched. In each hole, 2.0 kg of soil or laterites are collected using bar to mine and put in plastic bags for shipment to the analytical laboratory.
All rock outcroppings are noted in the field notes, their directions and dips are measured; an exhaustive description is made by the geologist, to facilitate the development of future 1 10 000 geological mapth. For the purposes of the geochemical sampling, quartz veins and rocks with something positive to the presence of gold (it is rocks rich in sulfide or boxworks or strongly injected of quartz veins) are harvested: 2.0 kg of rocks splinters are collected. Along the profiles, the trees are marked to facilitate their tracking on the ground: are noted the name of the profile and the number of the sample. The following coding is adopted for the identification of types of specimens (prefix followed by the number):
|Types of samples|
|TS1||Sample 1 ground Tinkoto Sou|
|NS1||Sample 1 soil of NGari Seekoto|
|F1 Ech.1||Vein 1 sample 1|
|P1M1||Well 1 of ore sample 1|
2. Organization of teams of Multimedia Geo-Chemical Sampling
The Geo-chemical prospecting program on the perimeters of Tinkoto Sou and NGari Seekoto was conducted by a team of field experts. The staff was structured as follows:
- 1 geologist-consultant, designer and coordinator of the work.
- 1 prospector geologist, responsible of the Geo-chemical sampling.
- 3 assistance for prospectors, responsible for the strategy.
- 1 Laboratory Assistant, tracking numbers and the weight of the samples.
- 6 daily maneuvers.
3. Evaluation of the Number of Samples
The number of samples by grid (perimeter) is given in the table below:
|Grid/Perimeter||Soil and Laterite||Roche||TOTAL|
4. Sending of Samples to the Laboratory SGS of Bamako
All samples which there are 517 (see table 3 below), were sent to the laboratory SGS Analabs in Bamako. The truck of the laboratory came on February 20, 2014, retrieve samples.
Table 3: List of samples sent to the laboratory.
5. Expected Results
The perimeters of NGari Seekoto and Tinkoto Sou are gold known for a very long time: they have been the object of operation artisanal gold eluvionnaire and Pocahontas.
The Geo-chemical survey was designed to:
- Allow from the surface anomalous follow (delimit) the gold bearing structures already known.
- Discover new anomalous areas, not known by the Stampeders (artisanal miners).
- Define the content of gold in gold-bearing quartz ore operated wells in the perimeter of Tinkoto Sou.
- Have the Geo-chemical information sufficient to begin, the 2nd part of the first phase i.e., of the trenching and prospecting wells, intended for the assessment of mine able gold resources in such perimeters.
For the interpretation of the future results of the analytical laboratory (SGS Analabs), it will be necessary to take account of the following information:
- The Geo-chemical background in the laterites of the region of Kedougou, is in general very low (< 10 ppb), that is why, here all values (results) higher or equal to 30 ppb, will be considered to be anomalous.
- In the 22 gold-bearing quartz ore samples, expected to levels in gold, over 3 g/t.
- The results of the other 18 samples of quartz vein should enable us to know whether or not these veins are gold surface (outcrop).
The results of the geochemistry were received from the SGS Lab on March 7, 2014 and are correct: The Geo-chemical background of laterites is less than 10 ppb (0.01 ppm or g / t). Whereby all results equal or superior to 0.02 ppm (g / t), can be considered anomalous. 20 of the 22 samples taken from the exploited pits of artisanal miners, provide greater than 1 g / t. 4 successive values are more than 50 g / t (Attached file). The average grade of the gold quartz vein is 48.39 g / t.
Geologist preparing maps, and program of tranches and pits:
|ORE SAMPLING||ORE CONTENT G/T|
The results as show on the map have led to some interpretations. The correlation of the anomalies shows oriented structures globally in the axis (N to NNE) directionally. Mineralization controlling factors, the most notable seems to be the disjunctive tectonic factor: faults, whose intersections represent areas of swelling (enlargement) of the gold mineralization. Three of these areas have been identified, among which, orpaille currently the site where 2 gold mineralized veins are known. On the basis of the results of the interpretation, we were able to project 7 trenches and 7 exploration wells. The depth of the trench will be 4-5 m and that of 12-15 Mr. Wells all these works will be sampled meter by meter and analyzed onsite. 25% of the total number of samples will be sent to the laboratory SGS Analabs of Kayes, for control. At the end of this work, an estimate of the gold potential and exploitable resources will be made. For the treatment of the samples on the spot, it will be necessary to install a small processing test unit. It will also provide a small production (3 T/H), with the ore selected, relatively strong (> 10 g/t).
Phase II consist of:
- Construction of the mining camp
- Installation of the test unit
- Ore testing and treatment methods.
Phase III consist of:
- Ore Stockpiling for production operation
- Installation of the large treatment unit for main ore production
- Site Plan
The mine site plan (Figure 7.4 1) shows the mine ore bodies in green and the processing plant located outside of the ore bodies and within 3 kilometers from the Gambian River.