Schlich ( German Schlich ) is a concentrate of heavy minerals that remain after washing in the water of natural loose deposits or specially crushed rocks for sintering. The composition of the concentrate includes grains of minerals with a density of more than 3000 kg / m³, resistant to physical and chemical weathering .
The extraction of concentrate is the basis of one of the oldest methods of prospecting and exploration of indigenous and placer minerals (the schlich method): diamonds , gold , platinum , tin , tungsten , mercury , titanium , zirconium , tantalum and niobium , some abrasives ( corundum , garnets ), fluorite , barite , etc.
Depending on the objectives of the geological work and washing methods, loose rock is washed either to the so-called gray concentrate , in which relatively light minerals remain, or to black (the final washing stage) containing grains of minerals with a high specific gravity. The final flushing (so-called lapping) of the concentrate is carried out in special schlich trays of various designs. The next stage of work with a concentrate residue (sample) is analytical and is carried out mainly in office conditions [1] .
Schlich method of prospecting and exploration of indigenous and alluvial minerals
Selection and route washing of concentrates is carried out at almost all stages of field geological research. Its ultimate goal is the analysis of data on the mineralogical composition of concentrates obtained during specialized studies and systematic schlich survey, accompanying geological surveying and prospecting works of various scales.
The main tasks solved using the schlich method:
- direct searches for placers and their root sources by schliché halos of useful minerals (native gold, platinum , cassiterite , tungsten , etc.);
- predictive estimation of areas by halos of satellite minerals;
- and, finally, the solution of general geological problems — the division and correlation of sedimentary strata and horizons that are remote from each other, the determination of lithosphere basins, the values of erosive incisions, paleogeographic reconstructions, etc.
The schlich method is considered to be some of the cheapest and easiest in exploratory geology [2] . However, there are also significantly different opinions about its simplicity and ease (see photo). The schlich method can be considered one of the oldest methods of searching for gold, a method that in ancient times was used by people who had the willpower, powerful intuition, but often did not even know how to read or write [3] . During the time of the so-called gold rush in Siberia , Alaska and California, the largest deposits of placer gold were discovered by washing the loose or crushed rocks to a fraction of the concentrate using only washing trays, Kyle , shovel, pelvic butor, intuition, physical strength, perseverance and personal courage of the prospector.
The schlich method is used for prospecting and exploration of shallow deposits of a valuable component. The method, in general, includes several stages:
- sampling for further washing
- processing of samples to the concentrate stage
- and mineralogical analysis of the latter (schlich analysis) [1] .
Bulk Sampling
Sampling for bulk analysis is carried out from loose surface deposits of almost any genesis , as well as from core or cuttings from shallow boreholes in loose rocks. Alluvium and coastal marine sediments are most thoroughly tested. On them, as a rule, manually, a mine is drilled ( pit , ditch , ditch (shallow pit, up to 1 m) or a small borehole using a hand drill ). Especially favorable for the study and sampling of natural outcrops, which are cleaned with a Kyle , a shovel and a knife. Loosened rock is selected from these and other similar prepared clearances into special test bags of a fixed volume made of cotton fabric, usually of thin tarpaulin .
| Gold-bearing core on the weathering crust of the chemical type of Cretaceous - Paleogene age from limestones obtained using a hand drill during route searches for gold. This material will also be washed in schlichny trays. August 2008. Here, and further in the photo gallery, excluding the shot with the nugget, a section of the watershed peneplains of Lake Teletskoye . | Ditching during geological prospecting for alluvial gold to select rocks for flushing. August 2009, Altai Mountains. | ||
| Rough flushing of rock on primitive flushing devices. Preparation of the rock for sizing, removal of the largest debris into dumps. August 2009, Altai Mountains. | Preparation of rock extracted from a ditch for primary washing on industrial instruments. August 2009, Altai Mountains. | ||
| Sludge washing is carried out around the clock. August 2009. Altai Mountains. | Finishing concentrates on a mountain stream in trays. August, 2009, Altai Mountains. | ||
| Alluvial weakly rounded gold in a heavy (black) concentrate in a schlich tray. The black mass is the sandy fraction of heavy minerals - primarily magnetite . August, 2009, Altai Mountains. | Well rounded gold nugget from the placer. Alaska , USA Weight - 63.6 g, dimensions - 4.5 × 3 × 0.6 cm. |
| In the morning, the washerman Kutsenko first of all examined the surroundings of his overnight stay. A kilometer from the place where he spent the night, he looked at a small stream for a long time, flowing down from the hillside to the river. He returned for the load, carried it to the mouth of the stream and pulled up a tent. He pulled it under a dry cliff according to all the rules and even held a drainage groove around. Then he took out a small ax from the backpack, on the blade of which the heel of the galoshes was planted, touched the tip and set to work on the boards. An hour later, Kutsenko was ready, as it were, a trough without end walls. On the bottom of the trough, ten centimeters, I pinned narrow transverse trims. He attributed this entire structure to the mouth of the stream. Choosing a site with good grass, Kutsenko began to cut the turf. He cut it into square pieces and stacked it. Then he adapted a piece of the board as an improvised back stand and moved the turf to the stream. Then he dug a drainage groove so that it fell on the edge of the cliff where the tent stood, and blocked a turf with a turf. Water flowed along the ditch and, as if from a cliff, fell into the water tunnel (as the simplest washing device is called in the prospecting language), which he made in the morning. After checking the structure, Kutsenko slightly eased the pressure of the water, for which he slightly opened the dam ... ... Putting on his backpack, Kutsenko examined the tent, the camp, as if remembering the signs, took a shovel and went up the river. He collected the first batch of sand into a backpack from a scythe, opposite the islet where he tore the onion. He carried it to a wooden trough, poured it out and, not stopping, went for a new portion. He continued this work until dark. The next day, Kutsenko was busy with the fact that he shoveled the soil that he had brought into the tunnel with a shovel. Water caught him and carried him into the river. He twice had to rake a pile washed at the end of the aperture. When the sand ran out, he drained the water and, using a regular spoon, collected the dark gray residue that had accumulated near the wooden planks and carefully washed the residue in the tray. What remained at the bottom of the tray did not please him. Among the dark mass of magnetite, in some places, individual spangles of gold shone through and there was still a small, almost dusty mass - about fifteen grams, as he determined by appearance. At the end of the day, Kutsenko wore the soil again, but he didn’t wash it on the scythe, but took it from the sides of the valley and went into the river twice, looking for shale brushes, which in themselves acted as a good flushing unit ... This went on day after day. Kutsenko went further away from his tent.Oleg Kuvaev [4] . Territory, with. 45-46 . |
Sampling from the alluvium of river valleys is carried out in areas most favorable for the accumulation of heavy minerals - on spits , rapids , below river bends, etc. The distance between the sampling points is determined by the scale of geological work. At a scale of 1: 200,000 (geological survey), this distance is 2 km or less, depending on the geomorphological situation; with a large-scale survey at 1: 50,000, this interval is less than 500 m. During detailed work, during geological prospecting and exploration, the schlich testing network thickens even more in the territory of the prospective area identified during geological surveys. During field work of any scale, it is advisable to flake out all exposed outcrops of loose rocks noted during the geological route , especially in difficult, highly forested mountain areas. Therefore, the schlich tray in the routes always carry with them [5]
In modern geology, bulk samples, with an average volume of about 0.02 m³, are washed in trays of various designs, in buckets, on cradles [6] , using screw separators or on concentration tables . To facilitate the diagnosis of minerals in the concentrate, the sample obtained after washing the sample is preliminarily divided into fractions. The magnetic fraction is sampled with a conventional magnet. It may contain magnetite , titanomagnetite and pyrrhotite in the concentrate. Using an electromagnet , the electromagnetic fraction is isolated: ilmenite , hematite , limonite , chrome spinels , tungsten , columbite , tantalite , pyrochlore , perovskite , sphene , xenotime , monazite , garnets , pyroxenes , amphiboles , olivine . The heavy fraction is released in the so-called heavy fluids. This fraction includes diamonds , gold , platinum , silver , scheelite , cassiterite , zircon , sulfides , cinnabar , corundum , rutile , barite , fluorite , topaz , andalusite , kyanite , sillimanite and anatase . The light fraction includes quartz , beryl and feldspars [7] .
Flow-dressing method
This method is based on obtaining concentrate by washing the crushed and crushed rock to a size of 1-2 mm. The method is used for express analysis of gold-bearing quartz veins , rare-metal pegmatites and for determination of accessory minerals in rocks.
Schlich analysis
Concentrated analysis consists in determining and describing minerals by fractions. It is usually performed under laboratory conditions using a binocular magnifier ( binocular microscope ), although sometimes an initial macro examination of especially interesting concentrates from the point of view of valuable components is also carried out directly in the field. In laboratories, individual fractions are subjected to quantitative spectral and other types of analyzes. The final document of schlich work is a map of schlich testing with an explanatory note, which sets out all the results of both field and desk analytical studies. The map also reveals promising areas for large-scale prospecting, exploration or exploitation of primary or alluvial deposits .
Determination of the composition and content of chemical elements in individual fractions and minerals in the concentrate significantly expands the predictive capabilities of the schlich method. For example, the determination by a spectrochemical method of the gold content in pyrite or pseudomorphoses of limonite from pyrite makes it possible to predict promising areas for prospecting for gold deposits. Additional important genetic and search information is obtained on the basis of studying the crystallographic forms of individual minerals, their twins and intergrowths. When assessing the prospects of closed areas (for example, with high forest cover or waterlogging), concentrates are studied from core and sludge from prospecting wells [8] .
Notes
- ↑ 1 2 Aristov V.V. Schlich / Mountain Encyclopedia. - M.: Soviet Encyclopedia, 1991. - V. 5. - S. 431-432.
- ↑ Schlichov method of placer prospecting (inaccessible link) . Dictionary on the geology of placers . Treasure hunter. Date of treatment November 20, 2010. Archived November 25, 2010.
- ↑ Geschichte des Goldwaschens im Rauristal (German) (unavailable link) . goldsuchen.at. Date of treatment November 20, 2010. Archived June 8, 2011.
- ↑ Oleg Kuvaev . Territory - Audiobook Do It Yourself, 2008.
- ↑ Rodygina V. G. Introduction to the schlich method: Textbook. - Tomsk: Tomsk State University, 1985. - 104 p.
- ↑ The cradle is an ordinary inclined board, or several boards well fitted to each other with sides at the edges, (gutter), sometimes, for smoothness, covered with linoleum . The cradle is installed with a slope of 0, 01 - 0, 04. In the head of this tray there are two wooden partitions for distributing water in a thin layer on an inclined surface. The enrichment on the cradle is due to the redistribution of the supplied debris material down the tray, where the heavy fraction is concentrated. The debris from the washing device is fed in portions of about 50 kg. Finishing up of a concentrate is carried out manually in schlichny trays. A very ancient method, however widely used, in particular, in Russia .
- ↑ Rodygina V. G. Introduction to the schlich method: Textbook. - Tomsk: Tomsk State University, 1985. - 104
- ↑ Aristov V.V. Shlikhova analysis / Mountain Encyclopedia. - M.: Soviet Encyclopedia, 1991.- V. 5. - S. 432.
Literature
- Zakharova E. M. Shlikhova method of mineral exploration. - M .: Nedra, 1989.
- Kosterin A.V. Schlicho-mineralogical and schlicho-geochemical methods of searching for ore deposits. - Novosibirsk: Science, 1972.
- Rodygina V. G. Introduction to the schlich method. - Tutorial. - Tomsk: Tomsk State University , 1985. - 104 p.
- Shilo N. A. Fundamentals of the doctrine of placers. - M .: Nauka, 1981 .-- 384 p.