Farm Widouw 309, 12 km south of Vanrhynsdorp, Western Cape Province
Marble has been quarried for dimension stone (both building stone and floor tiles) since the 1920s (Wybergh, 1932) but more recently, up until 1996 when the last working quarry closed (Namaqua Marble Industries (Pty) Ltd; Minerals Bureau, 1997), it was used for both cladding and floor tiles, with some stone being destined for the export market (Oosterhtiis, 1999). One deposit, a white dolomitic marble on the farm Moedverloren 208, 32 km northwest of Vanrhynsdorp, has been worked out (De Jager, 1976). Quarrying started in the area west and northwest of Vanrhynsdorp before finishing in the area south of Vanrhynsdorp on the farm Widouw 309.
Total resources could be 1000 million tons (Martini, 1987) and thicknesses of at least 35 m have been proved (De Jager, 1976; Oosterhuis, 1998). This area probably has the best potential for the economic exploitation of marble by small-scale miners and is the focus of the exploration programme described below.
The deposit has already been extensively prospected by ISCOR and Trans Hex Mining Limited; access to their previous drilling data would greatly reduce costs to future small-scale mining.
The target area on Widouw 309 has access to power, water and labour, and a railway-loading facility is present at Klawer, within 15 km, for the transport of raw blocks and slabs. However, it would be more beneficial to construct a local factory for the cutting and polishing of slabs and tiles thereby adding value to the finished product.
Geology
Marble occurs in an area centred on Vanrhynsdorp, in the Neoproterozoic Widouw Formation of the Gariep Supergroup (De Beer et al., 2002. The degree of metamorphic recrystallization of the original marine limestone is controlled by the amount of shearing (De Beer et al., 2002). The mostly finely crystalline marble is predominantly calcitic, but in places, dolomitic. Colours are generally bluish-grey, but locally white and rarely black (Wybergh, 1920, 1932; De Jager, 1976; De Beer et al., 2002). Carbonaceous strinaers are common.
The marble on Widouw 309 is a pure calcitic marble as indicated by the following average geochemical analyses of 138 samples (Martini, 1987): SiO2 = 0.9%; AI2O3 = 0.23%; Fe2O3 = 0.3%; CaO = 52.9%; MgO = 1.5%; P205 = 0.1%; S = 0.012%; RCO3 = 97.6%. The strata are broadly folded with fold axes trending northwest and dips less than 45°.
Marble has been quarried for dimension stone (both building stone and floor tiles) since the 1920s (Wybergh, 1932) but more recently, up until 1996 when the last working quarry closed (Namaqua Marble Industries (Pty) Ltd; Minerals Bureau, 1997), it was used for both cladding and floor tiles, with some stone being destined for the export market (Oosterhtiis, 1999). One deposit, a white dolomitic marble on the farm Moedverloren 208, 32 km northwest of Vanrhynsdorp, has been worked out (De Jager, 1976). Quarrying started in the area west and northwest of Vanrhynsdorp before finishing in the area south of Vanrhynsdorp on the farm Widouw 309.
Total resources could be 1000 million tons (Martini, 1987) and thicknesses of at least 35 m have been proved (De Jager, 1976; Oosterhuis, 1998). This area probably has the best potential for the economic exploitation of marble by small-scale miners and is the focus of the exploration programme described below.
The deposit has already been extensively prospected by ISCOR and Trans Hex Mining Limited; access to their previous drilling data would greatly reduce costs to future small-scale mining.
The target area on Widouw 309 has access to power, water and labour, and a railway-loading facility is present at Klawer, within 15 km, for the transport of raw blocks and slabs. However, it would be more beneficial to construct a local factory for the cutting and polishing of slabs and tiles thereby adding value to the finished product.
Geology
Marble occurs in an area centred on Vanrhynsdorp, in the Neoproterozoic Widouw Formation of the Gariep Supergroup (De Beer et al., 2002. The degree of metamorphic recrystallization of the original marine limestone is controlled by the amount of shearing (De Beer et al., 2002). The mostly finely crystalline marble is predominantly calcitic, but in places, dolomitic. Colours are generally bluish-grey, but locally white and rarely black (Wybergh, 1920, 1932; De Jager, 1976; De Beer et al., 2002). Carbonaceous strinaers are common.
The marble on Widouw 309 is a pure calcitic marble as indicated by the following average geochemical analyses of 138 samples (Martini, 1987): SiO2 = 0.9%; AI2O3 = 0.23%; Fe2O3 = 0.3%; CaO = 52.9%; MgO = 1.5%; P205 = 0.1%; S = 0.012%; RCO3 = 97.6%. The strata are broadly folded with fold axes trending northwest and dips less than 45°.
