HISTORY

Mimosa was acquired by Zimasco from Union Carbide in 1993.  Zimasco piloted platinum mining in Zimbabwe by resuscitating the operation and steadily increasing production to 1,000 tonnes per day by 1998.  In July 2001, Implats acquired a 35% stake in Mimosa for a consideration of R246 million.  This stake was increased to 50% with a further acquisition of 15% in August of the following year.  Aquarius acquired a 50% stake in Mimosa during the same year. 

GEOLOGY

Although platinum was first discovered in the Great Dyke in 1918, its exploration was overshadowed by that of the Bushveld Complex in South Africa.  Focus has returned to the Great Dyke in recent years, following the increase in demand for platinum and given that much of the shallow mineral resources in the Bushveld Complex are spoken for.

The Great Dyke is a layered complex similar to that of the Bushveld Complex.  It extends for 550 kilometres and has a maximum width of 11 kilometres.  Within the Great Dyke four geological complexes are known to contain PGM and base metal deposits.  These are the Wedza Complex (Mimosa – Aquarius and Implats), Selukwe Complex (Unki – Anglo Platinum), the Hartley Geological Complex (Hartley and Ngezi Platinum Mines - Zimplats) and the Musengezi Complex.  The Hartley Geological complex is the largest of the PGM bearing complex’s containing 80% of the known PGM resources in Zimbabwe.

The stratigraphy is broadly divided between a lower ultramafic and an overlying mafic sequence.  The ultramafic sequence hosts the P1 pyroxenite, directly below the mafic-ultramafic contact, which in turn hosts the economic PGM-bearing Main Sulfphide Zone (MSZ).  The MSZ is a continuous layer between 2 and 3 metres thick that forms an elongated basin.  Optimal mineralisation varies and, in contrast to the Bushveld Complex, is often difficult to follow visually.  Peak values for the PGM and base metals are commonly offset, while the proportions between platinum and palladium also vary vertically.

The Mimosa lease encompasses four areas namely North Hill, South Hill, Mtshingwe Block and Far South Hill.  These areas covering some 6,590 hectares are separated by major faults.  Mimosa’s mineral resources are currently estimated at 5.2 million platinum ounces.  Unlike much of the Great Dyke, Mimosa has a well-defined grade profile with an identifiable reef horizon marker facilitating grade control. 

MINING

The orebody is extremely shallow and mining commences at a depth of 60 metres below surface and currently extends to a depth of approximately 200 metres. The bord and pillar mining method is employed and stoping widths average around 2 metres. Mimosa is a fully mechanised mining operation.

METALLURGY

Mimosa has a concentrator plant on site, where initial processing is done.  Concentrate is transported by road to Impala Platinum’s Mineral Processes in Rustenburg in terms of a life-of-mine offtake agreement with Impala Refining Services (IRS).

INDIGENISATION

The Zimbabwean indigenisation regulations were gazetted early in 2010 and require foreign companies to indigenise 51% of their shares or interests within five years.  Mimosa is currently reviewing its options in this regard.

SUSTAINABLE DEVELOPMENT

Mimosa is committed to social development initiatives and engages in, develops and builds community relationships.  It takes responsibility for economic, social and environmental issues that impact its people, communities and environments and is involved in a number of community projects in the area.

Mimosa - key statistics
				FY2010	FY2009	FY2008	FY2007	FY2006
Production
	Tonnes milled	(000 t)		2,277	2,111	1,732	1,692	1,532
	Headgrade (5E + Au)	(g/t)		3.86	3.87	3.85	3.66	3.72
	Platinum in concentrate	(000 oz)		101.2	91.5	76.6	78.2	72.2
	PGM in concentrate	(000 oz)		210.3	189.3	158.9	163.3	150.5
Mining cost of sales		(Rm)		1,072	1,008	594	523	414
	Mining operations	(Rm)		665	582	367	285	269
	Concentrating operations	(Rm)		183	215	104	79	63
	Other	(Rm)		224	211	123	159	82
Total cost		(Rm)		913	865	538	423	371
	per tonne milled	(R/t)		401	412	311	250	242
		($/t)		53	45	43	35	38
	per platinum ounce in concentrate	(R/oz)		9,018	9,454	7,023	5,413	5,133
		($/oz)		1,194	1,041	967	753	803
Financial ratios
	Gross margin	(%)		48.0	20.1	69.0	69.0	52.5
Capital expenditure		(Rm)		255	555	289	113	208
		($m)		34	61	40	16	33
Safety
	LTIFR   (per million man hours worked)			0.35	0.52	0.88	1.74	1.40
	FIFR     (per million man hours worked)			-	-	0.13	0.48	-
Labour complement (including contractors)				1,802.0	1,931	1,796	1,633	1,630