Gugliel­mo Mar­ti­naglia, an Ital­ian min­er, blast­ed through the sur­face open­ings of the Sterk­fontein Caves in 1896. At rough­ly the same time, mem­bers of the South African Geo­log­i­cal Soci­ety report­ed inter­est­ing cave for­ma­tions and fos­sils in the caves. Mar­ti­naglia, how­ev­er, want­ed to exploit the lime in the cave for its com­mer­cial poten­tial in the gold min­ing and con­struc­tion industries.

The geol­o­gists called for the Sterk­fontein Caves to be pro­tect­ed in the 1890s. David Drap­er, a respect­ed geol­o­gist of the time, per­suad­ed the min­ers to pre­serve the main cave because of its sta­lac­tites, sta­lag­mites and pris­tine under­ground lake, but min­ing con­tin­ued in the area. Signs of the lime work­ers’ activ­i­ties can still be seen.

David Draper

David Drap­er

From about the 1920s, the caves start­ed to become pop­u­lar with tourists. Sou­venir col­lec­tors took or pur­chased fos­sils from the site. The own­er at the time, RM Coop­er, wrote a book­let in which he encour­aged vis­i­tors to come to the Sterk­fontein Caves to find the miss­ing link”.

In 1935, Trevor Jones, a stu­dent of Pro­fes­sor Ray­mond Dart, who was head of the Depart­ment of Anato­my at the Uni­ver­si­ty of the Wit­wa­ter­srand in Johan­nes­burg, col­lect­ed fos­sil mon­keys from lime min­ers’ dumps at Sterk­fontein. In 1937, he pub­lished a descrip­tion of an extinct species he called Para­pa­pio broo­mi, in hon­our of Dr Robert Broom, who was a famous palaeon­tol­o­gist based at the Trans­vaal Muse­um in Pre­to­ria. In turn, Broom him­self described a sec­ond species of mon­key from Sterk­fontein as Para­pa­pio jone­si, in hon­our of Jones. In 1936, two more of Dart’s stu­dents, Hard­ing le Riche and GWH Schep­ers, also col­lect­ed fos­sil mon­keys from the lime min­ers and took them to Broom.

Broom accom­pa­nied the stu­dents to Sterk­fontein on August 9 1936 and asked the mine man­ag­er, George Bar­low, if he had ever found a fos­sil like the Taung Skull, the type spec­i­men of Aus­tralo­p­ithe­cus africanus, which had been found in 1924 at Taung in the North West Province of South Africa. Taung is now also offi­cial­ly part of the Cra­dle of Humankind World Her­itage Site.

Eight days lat­er, on August 17 1936, Bar­low hand­ed Broom the nat­ur­al brec­cia cast of the inside of a brain­case. Broom recog­nised this as a pri­mate with a chim­panzee-sized brain. He looked over the dumps and dis­cov­ered parts of the crushed skull match­ing the brec­cia cast. The teeth were human-like: it clear­ly rep­re­sent­ed an adult Aus­tralo­p­ithe­cus. Broom named the spec­i­men (cat­a­logued as TM 1511) Aus­tralo­p­ithe­cus trans­vaalen­sis (“south­ern ape of the Trans­vaal”), although it has since been reclas­si­fied as Aus­tralo­p­ithe­cus africanus, the same as the Taung Child. Broom went on to recov­er many oth­er spec­i­mens of Aus­tralo­p­ithe­cus from the lime min­ers’ dumps.

In the 1940s, the dis­cov­ery of a long-extinct hunt­ing hye­na fos­sil from lime min­ers’ dumps of the low­er Mem­ber 2 in the Sil­ber­berg Grot­to of Sterk­fontein led Broom to appre­ci­ate the Pliocene antiq­ui­ty of the deposits, which have more recent­ly been dat­ed to between about 4.2-million and 3.3-million years old.

Thus, although the palaeon­to­log­i­cal poten­tial of Sterk­fontein was recog­nised in the late 19th cen­tu­ry, it was only after Broom’s dis­cov­ery of an aus­tralo­p­ithecine skull in 1936 that seri­ous sci­en­tif­ic exca­va­tions began.

The min­ing no doubt destroyed much of the palaeoan­thro­po­log­i­cal and archae­o­log­i­cal record in the area. Broom wrote in 1946:

It is sad to think that for near­ly 40 years no sci­en­tist ever paid the slight­est atten­tion to these caves and prob­a­bly some dozens of skulls of ape-men and all the bones of their skele­tons were burnt in lime kilns.”

But most fos­sils were prob­a­bly lost due to the min­ers giv­ing away or sell­ing fos­sils and pieces of brec­cia to vis­i­tors as curios.

Min­ing in South Africa

Gold was dis­cov­ered on the Wit­wa­ter­srand in the 1880s, prompt­ing hun­dreds of thou­sands of prospec­tors from all over the world to rush to the area in the hope of find­ing their fortunes.

Lime was need­ed in the chem­i­cal extrac­tion of gold. The gold min­ing indus­try thus sparked a sec­ond indus­try in lime min­ing. When lime was dis­cov­ered in the Sterk­fontein Caves in con­sid­er­able quan­ti­ties, min­ers con­verged on the site.

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Entrance to the old Krom­draai mine

Gold was first dis­cov­ered on the Wit­wa­ter­srand area in 1884, lead­ing to the biggest gold rush the world has ever seen. Many small mines sprang up as prospec­tors mined sur­face and shal­low deposits, then sank shafts into the ground and blast­ed out tun­nels. The mines and pro­cess­ing works had a con­sid­er­able impact on the envi­ron­ment through the appear­ance of under­ground and sur­face work­ings, spoil heaps, pro­cess­ing plants and mine build­ings. The pro­cess­ing works used cyanide and oth­er chem­i­cals which pol­lut­ed the ground and water. The old Krom­draai gold mine near Sterk­fontein can be vis­it­ed in the Cra­dle of Humankind, where widescale prospect­ing also took place.

The Sterk­fontein Caves attract­ed min­ers because of the exten­sive deposits of cal­ci­um car­bon­ate in the form of sta­lac­tites, sta­lag­mites and flow­stone. Cal­ci­um car­bon­ate is a chem­i­cal com­bi­na­tion of cal­ci­um, car­bon and oxy­gen. When burned, it yields lime – what the min­ers were real­ly after.

Lime and gold min­ing changed the land­scape in and around the Cra­dle of Humankind World Her­itage Site forever.