S parkirišča pred predorom Ljubelj boste ob zmerni hoji do zaklada potrebovali dobri 2 uri. Za obisk zaklada je potrebna primerna planinska oprema. Obisk zaklada je na lastno odgovornost. Vstop v rudnik je smrtno nevaren.
From the parking at Ljubelj you will need a good 2 hours moderate walking to the cache location. Appropriate mountain equipment is needed to visit the cache. A visit is at your own risk. Entry to the mine ios extremly dangerous!
Mangan
Mangan je sivkasto-bela kovina. Na videz je podobna železu. Je trdna in zelo krhka kovina, ki zlahka oksidira. Mangan se težko tali. V naravi se pojavlja večinoma v obliki minerala. Okoli 90 % vsega mangana se uporablja pri proizvodnji jekla v obliki feromangana. Mangan v jeklu izboljša njegovo čvrstost, saj razžveplja surovo železo. Mangan je pomemben tudi pri proizvodnji alkalno-manganovih baterij.
Slika 1: Mangan
Element ima tudi pomembno biološko vlogo, saj je sestavni element različnih encimov (eden najpomembnejših elementov v ciklusu fotosinteze).
Slika 2: Mangan v periodnem sistemu
V naravi so manganovi oksidi v raznih mineralih. Že dolgo so poznani kot naravna barvila, ki jih je uporabljal človek. Tako je v črni barvi v 17.000 let starih slikarijah v jami Lescaux dokazana prisotnost manganovih oksidov. V Rimskem cesarstvu so manganove spojine uporabljali že od 4. stol. pr. n. št. pri izdelavi stekla (steklo bi se ob uporabi manganovih mineralov obarvalo rjavkasto-vijolično).
Mangan na Begunjščici
Največji rudnik mangana na Begunjščici leži tik ob današnji markirani poti med Prevalom in Roblekovim domom. Iz te rude je bila v jeseniški železarni leta 1872 prvič v plavžu izdelana manganova železova litina. Na Begunjščici so pridobili okrog 130.000 t manganove rude (vsebovala je povprečno 30 % mangana). Tu so pridobili kar 79 % vseh slovenskih manganovih rud, ki so bile predelane v jeseniški železarni. Do leta 1870 so letno izkopali le nekaj ton rude, med letoma 1871 in 1875 pa se je pridobivanje povečalo iz 7,3 t na 76 t letno. Zgradili so tudi žičnico, ki je pospešila in pocenila transport (ruda je bila v dolini v 8 minutah). Prej so rudo v dolino vozili s sanmi ali z enoosnimi vozovi brez zadnjih koles. Tako je zadnji del voza zaviral z drsenjem po tleh. Pridobivanje rude v rudniku se je prenehalo leta 1915.
Slika 3: Manganov dendrit iz jurskih plasti Begunjščice
Na Begunjščici so plasti večinoma skrilavega kremenovega laporovca, debele od 1,5 metra do nekaj metrov, ki so v spodnjem delu impregnacijsko orudene s črnimi drobnozrnatimi manganovimi oksidi, med zgornjeliasnimi plastmi skladnatega in ploščastega sivega, rjavkastega in rdečkastega apnenca z rožencem in amoniti.
Rudna plast je debela od 0,6 do 4 m. Med rudnimi manganovimi minerali po količini močno prevladuje braunit. Sledijo mu todorokit, piroluzitin v sledovih birnessit, romanechit (kriptomelan), goethit in hematit. Vsi so drobnozrnati. V kasneje nastalih razpokah pa so žarkasti ali vlaknasti, do 3 mm dolgi kristali piroluzita s kovinskim sijajem. V manganovi rudi na Begunjščici so v žilicah tudi kristali kalcita. Pod Roblekovim domom so v razpokah našli tudi žarkasti aragonit pretežno bele barve s steklastim sijajem.
Geološko karto območja si lahko ogledate na: http://biotit.geo-zs.si/ogk100/
Naloge za vpis zaklada:
- Oglejte si informacijsko tablo pred vhodom v rudnik. Ena izmed slik nad besedilom prikazuje manganovo rudo, ki so jo kopali v rudniku. Opišite jo. Kaj je prikazano na drugih dveh slikah nad besedilom?
- Oglejte si sliko manganovega dendrita v opisu zaklada. Ali ga opazite kje na površju okoli vhoda?
- Kdaj je prišlo do povečanega izkopavanja rude? S pomočjo besedila zaklada in besedila na informacijski tabli zapišite, kaj je botrovalo k povečanemu izkopavanju.
- Neobvezno: zaželena je kakšna fotografija z vašega obiska zaklada.
POMEMBNO!
- Preden vpišete obisk zaklada, pošljite odgovore preko GC. Takoj potem lahko vpišete obisk zaklada na spletu - ne potrebujete dodatnega dovoljenja. Če bo kaj narobe, vas bom kontaktiral.
- Vpisi brez ustrezne spremljajoče e-pošte, ki vsebuje pravilne odgovore, bodo izbrisani!
- Vpisi, ki vsebujejo odgovor bodo izbrisani!
Manganese
Manganese is a greyish-white metal. It looks like iron. It is a solid and very fragile metal that easily oxidizes. Manganese is difficult to dull. It occurs naturally in the form of a mineral. About 90% of all manganese is used in the production of ferro-magnesium steel. Manganese in steel improves its firmness, as it take sulfur from raw iron. Manganese is also important in the production of alkaline-manganese batteries.
Figure 1: Manganese
The element has also an important biological role, as it is an integral element of various enzymes (one of the most important elements in the photosynthesis cycle).
Figure 2: Manganese in periodic table
In nature, manganese oxides are in various minerals. They have long been known as natural dyes used by humans. Thus, the presence of manganese oxides in the 17,000-year-old paintings in the Lescaux cave has been proved in black color. In the Roman Empire, manganese compounds have been used since the 4th century BC in the manufacture of glass (the glass would be brownish-violet with the use of manganese minerals).
Mangan at Begunjščica
The largest manganese mine in Begunjščica lies right on today's marked path between Preval and Roblekov dom. Factory of iron in Jesenice in 1872 manufactured first manganese iron casting in the world. About 130,000 tons of manganese ore were mined at Begunjščica (it contained on average 30% manganese). That was 79% of all Slovenian mined manganese minerals, which were processed in the ironworks of Jesenice. By the year 1870, only a few tons of ore were excavated annually. Between 1871 and 1875, the production increased from 7.3 t to 76 t per year. They also built a cable car that accelerated transport and lowered costs of the transport (the ore was in the valley in 8 minutes). Previously, the ore was transported to the valley by snowmobiles or single-axle carts without rear wheels. Thus, the back of the cart was braking by scrolling on the ground. The mining of the mine ended in 1915.
Figure 3: Manganese dendrite from jurasic layers of Begunjščica
In Begunjščica layers are mostly of slate quartz marl, thick from 1.5 meters to a few meters, which are impregnated in the lower part with black fine-grained manganese oxides, between the upper lias of layered and flat gray, brownish and reddish limestone with roséne and ammonite. The ore layer is 0.6 to 4 m thick. Among the minerals of manganese minerals, the quantity is strongly dominated by braunite. Followed by todorokit, pyrolucytin in traces of birnessite, romanechite (cryptomelan), goethit and hematite. They are all fine-grained. In later formed cracks are brittle or fibrous, up to 3 mm long crystals of pyrolyzite with metallic glow. In the manganese ore on Begunjščica, crystals of calcite are also present. Underneath the Roblekov dom, the aragonite was found. It is predominantly white with glassy glow.
You can see the geological map of the area at: http://biotit.geo-zs.si/ogk100/
Tasks for logging:
1. Take a look at the information board in front of the mine entrance. One picture shows manganese ore from Begunjščica. Describe the ore. What is shown on the other two images above the text?
2. Look at description of the earth cache and search for the picture of manganese dendrite. Can you see it near the entrance to the mine?
3. When has the ore mining increased? Use the text of the cache and the text on the information board and write what caused an increased excavation.
4. Optional: Any photo from your treasure visit is welcome.
IMPORTANT!
- Send answers through GC profile before logging. After that you can log - you don't need an additional permission to log I will contact you if something is wrong.
- Logs without an accompanying e-mail containing correct answers will be deleted!
- Logs containing the answer will be deleted!
Viri / References:
https://sl.wikipedia.org/wiki/Mangan
http://www.wikiwand.com/bs/Mangan
https://www.inorganicventures.com/element/manganese
http://www.zobodat.at/pdf/Scopolia_Suppl_3_0119-0124.pdf
http://www.delo.si/druzba/znanost/geoloska-zakladnica-nad-trzicem.html