Gold Occurrences in Benin

Map of Benin

Mineral resource development is controlled by the Office Béninoise des Mines (OBEMINES). Benin has been revising its mining laws in order to attract foreign investment.

Benin has gold, iron ore and phosphate potential and has awarded several exploration licenses for gold exploration in the country to foreign investors. There are deposits of brick and china clay, feldspar, the Loumbu Loumbo low grade iron ore deposits and the Mekrou phosphate deposits. The development of the Loumbu Loumbu and Mekrou deposits hinges on the proposed development of a hydro electric power scheme that is to be constructed on the Mekrou River. Gold mineralization has been identified in the Atacora and Alibori regions, where hard rock and alluvial deposits are known to exist. At Alibori, a 350 km2 prospective area includes alluvial and vein hosted gold occurrences.

Major sources of alluvial gold and diamonds can be found in the Birimian rocks that are found in Ghana, the Ivory Coast, Mali and Burkina Faso   These rocks derive their name from the Birim River thay are one of the main tributaries of the Pra River of Ghana.  The same rocks also contain the country’s most important diamond deposits.  Diamonds are produced in Ghana and Mali that are the second and third largest producers in Africa.

The gold and diamond bearing rocks are called the Birimian Terranes that are composed of a mix 0f meta-volcanics, meta-sedimentary and rocks that are plutonic in nature.  Almost half of the rocks found in the southern part of the West African Craton are alkaline granites.  These rocks formed in a period of about 50 million years between 2,200 and 2,100 Ga years ago.

It is believed the Birimian Rocks that stretch across the countries that are to the north of the Gulf of Guinea formed when a series of island arcs were driven together forming a series of parallel belts that trend to the northeast in a belt that is about 40 to 50 kilometers wide.  Many of the volcanic rocks have been metamorphosed into greenschist facies.

Although most of the gold mined in the country is recovered by artisanal miners from the Birimian Terrane it has recently discovered more gold is found in the overlaying conglomerate of the Tarkewian formation.  The gold does not have its origin in the Birimian Terrane. 

There are several varying theories about the origin of the Birimian Terrane.  One theory holds the rocks were formed by the collision of the Archean Cupixi-Carajas craton of the Southern Guiana Shield.  Another theory that is more widely accepted is the terrane has it origins in a mid-oceanic series of volcanic island arcs that formed a crust that was then thrust faulted onto the West African Craton that was later compressed into a series of folds.

During the recent civil war in Benin foreign investment literally dried up, but with the onset of peace it is beginning to flow once again.

Gold Occurrences in Pennsylvania

Pennsylvania has a long and rich tradition of mining especially for anthracite and bituminous coal as well as iron. What is not generally known however is the state is also produced a considerable amount of gold. It has a well-trained workforce of miners many of whom have a tendency to be prospectors. Because of this some iron miners down around Cornwall have actually produced more than 61,000 ounces of gold while they were mining the magnetite iron ore. Aside from the mine at Cornwall another mine that reportedly produced gold from magnetite was the Grace mine in Morgantown.

There were a series of three openings to the iron deposit in Cornwall located at Big Hill, Middle Hill and Grassy Hill that were originally owned by the Cornwall Ore Banks Co., but were eventually owned by Bethlehem Steel who eventually closed the mines in 1979.  This deposit of magnetite was produced by the replacement of limestone by hydrothermal activity during the Jurassic from a diabase intrusive, so in effect the deposit is a skarn.

The eastern part of the state is covered with crystalline rocks producing potential gold lodes as well as placer gold. This gold weathers out of the crystalline rocks and is collected in the rivers and streams of eastern Pennsylvania. This is not the only source of gold however, in the northern part of the state the last glacier left placer gold in the terminal moraines found in Pennsylvania.

There are several streams producing placer gold that came in Lancaster and York Counties in glaciers that have advanced into the state during the past million years. Any of these glaciers were capable of bringing gold down from Canada where one of the richest gold belts the world the Abitibi is found in Québec and Ontario. According to some geologists there have been as many as 24 episodes of glaciation that have affected the northern part of the United States in the past 2.5 million years.

Although the eastern part of the state is mostly covered with crystalline rocks that produce gold as lode gold that weathers out so it becomes placer gold that collects in the rivers and streams found in eastern Pennsylvania.

One of the places where gold has been found is along the Susquehanna River where it has been found as both nuggets and flakes of gold. Generally Wyoming County has been a good place to look for gold as well as in the surrounding counties.  In York County  placer gold is associated with the deposits of diabase that make up the tops of many ridges. The action of weathering releases the gold from bedrock allowing it to migrate downhill into the streams and rivers in the area.

During the Civil War the great battle at Gettysburg was fought on some of these diabase ridges with names like Little Round Top or Cemetery Ridge. There is no doubt that the rivers and streams around the Gettysburg Battle Site undoubtedly contain gold. 

The best way to find out where the gold is in Pennsylvania is to research old newspapers and town histories.  The state only keeps track of commercial mining operations and not that of individual prospectors. Old newspapers are often the source of stories about where one of the local citizens has found gold in their town.

Helpful Links:

Gold Pennsylvania prospecting, http://www.e-goldprospecting.com/html/gold_pennsylvania_prospecting.html

Eastern Gold, http://doccopper.tripod.com/gold/easternAu.html

Jeri Jones http://www.jonesgeo.com/home.htm

http://home.epix.net/~prospect/index101.html

There are several gold prospecting clubs that are active in Pennsylvania that can supply more information about Pennsylvania gold.

Our thanks to Stephen Shanks of the Pennsylvania Geological Survey for additional information.