The Buildint} and Ornamental Stone Resources of Tasmania ~,......-~ Tasmania Department of Resources and Energy Division of Mines and Mineral Resources - Report 1990/31 The building and ornamental stone resources of Tasmania by C. E. Sharples Report prepared for The Tasmanian Development Authority and Tasmania Department of Resources and Energy (Division of Mines and Mineral Resources) April 1990 • • • I • • • CONTENTS Page No. 1. INTRODUCTION 1 1.1 Natural stone as a building and ornamental material 1 1.2 Modern stone use 1 1.3 Purpose of this report 2 1.4 Scope of the project 3 1.5 Previous work 3 1.6 Tasmanian dimension stone quarry operators 4 1.7 Acknowledgements 5 2. EXPLORATION, EVALUATION AND DEVELOPMENT OF STONE RESOURCES 6 2.1 Exploration and testing procedures 6 2.1.1 Reconnaissance assessment of building and ornamental stone resources 6 2.1.2 Detailed exploration and evaluation procedures 8 2.2 General cri,teria and legal requirements for building stone quarry sites (all stone types) 1 5 2.2.1 Quarry site suitability and viability 1 5 2.2.2 Legal and environmental requirements for opening and operation of building stone quarries 1 6 2.3 Criteria for high quality and durability stone (all types) 1 8 2.4 Stone testing methods 31 3. SUMMARY OF PROMISING STONE RESOURCES IN TASMANIA 34 3.1 Introduction 34 3.2 Sandstone 34 3.3 Slate 36 3.4 True Granite 37 3.5 Black Granite 39 3.6 Other Granite 40 3.7 Marble 40 3.8 Serpentines 41 3.9 Other Stone types 41 4. SANDSTONE 55 4.1 Definition and description 55 4.2 Sandstone applications 57 4.3 Sandstone quarrying in Tasmania 58 4.4 Sandstone sources and prospects in Tasmania 58 4.5 Evaluation of sandstone sources and prospects in Tasmania 59 5. SLATE 82 5.1 Definition and description 82 5.2 Slate applications 84 5.3 Slate quarrying in Tasmania 84 5.4 Slate sources and prospects in Tasmania 85 5.5 Evaluation of slate sources and prospects in Tasmania 87 6. GRANITE ("True Granite") 101 6.1 Definition and description 101 6.2 Granite applications 103 6.3 Granite quarrying in Tasmania 104 6.4 True granite sources and prospects in Tasmania 105 6.5 Evaluation of true granite sources and prospects in Tasmania 108 7. BLACK "GRANITE" 145 7.1 Definition and description 145 7.2 Black granite applications 148 7.3 Black granite quarrying in Tasmania 149 7.4 Black granite sources and prospects in Tasmania 149 7.5 Evaluation of black granite sources and prospects in Tasmania 153 8. OTHER "GRANITE" 192 8.1 Definition and description 192 8.2 "Other granite" applications 196 8.3 "Other granite" quarrying in Tasmania 196 8.4 "Other granite" prospects in Tasmania 197 8.5 Evaluation of "other granite" prospects in Tasmania 199 9. MARBLE 213 9.1 Definition and description 213 9.2 Marble applications 217 9.3 Marble quarrying in Tasmania 218 9.4 Marble prospects in Tasmania 218 9.5 Evaluation of marble prospects in Tasmania 220 10. SERPENTINE 232 10.1 Definition and description 232 10.2 Serpentine applications 233 10.3 Serpentine quarrying in Tasmania 233 10.4 Serpentine prospects in Tasmania 233 10.5 Evaluation of serpentine prospects in Tasmania 235 11. OTHER STONE TYPES 241 11.1 Introduction 241 11.2 Limestone and dolomite prospects in Tasmania 241 11.3 Travertine deposits in Tasmania 243 11.4 Miscellaneous other stone types 243 GLOSSARY OF TERMS 248 REFERENCES 251 APPENDIX ONE: STONE PROSPECTS DATA BASE 260 A 1.1 Introduction 260 A 1.2 Area, site and sample numbering system 260 A 1.3 Database records 265 1 CHAPTER ONE INTRODUCTION 1.1 Natural stone as a building and ornamental material Natural dimension stone has been extenSively used as a building material in the past. With the advent of cheap artificial building materials the use of stone changed from being a normal building material to becoming increasingly seen as a prestige material. The aesthetic qualities of stone have not, in the writer's opinion, been surpassed by artificial materials, and it is most likely that stone will continue to be favoured into the future. Human society uses most of the Earth's mineral and stone resouces in a highly processed form, in which they lose their original character (eg, metals, industrial minerals). The use of stone as a building material is different, in that it is precisely the natural aesthetic qualities of the material for which. it is valued. The fact that architects and others commonly favour the use of stone in a building whenever budgets will allow it, suggests that the colours, textures and structures of natural stone have a universal appeal which the artificial alternatives of concrete, brick, glass and steef cannot match. It is tempting to suggest that even after thousands of years of cultural development in urban environments, people still find a totally artificial environment somewhat alienating. Thus, the use of natural building materials in the urban environment may take some of the artificial "edge" off that environment. Given that the human mind evolved in, and can thus be at ease in, a predominantly natural environment, the use of pleasing natural elements, including stone, may serve in a small way to reduce the stress of modern urban life. Of course, this cannot alone account for the use of stone in modern buildings, especially in such cases as the modern use of granite cladding on high-rise buildings where the natural qualities of the material are less obvious. In fact, a major reason for the current boom in the use of stone is simply that good stone can be a more durable material than many of the artificial alternatives. The sought after nature of building stone means that stone can command a high price for relatively small volumes of good material. A moderate amount of stone, sandstone, granite and slate, is currently quarried in Tasmania for building purposes. Although some exploration and evaluation of stone resources has previously been carried out, there has been a need for a systematic evaluation of Tasmania's potential dimension stone resources, whose results can be made public in order to encourage the utilisation of Tasmania's full range of stone resources. 1.2 Modern stone use Over the last 25 years or so the use of stone in major buildings has increased dramatically. The most important applications of stone today are as veneers (wall cladding, exterior and interior) and as paving. Stone furniture (including bench-tops, tables, etc) is also an important application, while gravestones remain a mainstay of the industry. The traditional use of stone as massive masonry blocks has almost disappeared (except in restoration work) due to the high costs involved, and has been replaced by the use of thin veneers. Although much marble has been used for external veneers, the durability problems associated with marble are resulting in a trend towards greater use of more durable granite veneers, particularly on high-rise buildings. The use of granites is presently booming, particularly in 2 places such as Hong Kong and Japan. Sandstone and limestone, being of inherently lower durability than granite, are not well suited to high-rise exterior cladding, but can be successful exterior claddings on low-rise buildings. (Although limestone has rarely been used on Australian buildings during the last 30 years, it is widely used in Europe and the USA). Comparatively low-durability stones can be successfully used in interior applications such as foyers, furniture, and so on. Marble, with its wide range of appealling colours and textures, is favoured for such purposes, although serpentine, travertine and granites are also widely used. Slate, which can be very durable, is commonly used both internally and externally for wall cladding and paving. Granites are used for paving, but may not hold a good polish in areas of high traffic. Softer, less durable stones such as sandstone and serpentine are not generally suitable for paving, although they are also used. Stone is generally required to be of fairly even colour and texture for use in covering large areas, such as external cladding. However, vari-coloured or patterned stone can find applications in relatively small features intended to be viewed at close range, such as feature walls, prestige foyers, stone furniture, and fireplaces. 1.3 Purpose of this report The aim of· this project is to conduct a comprehensive survey of both the existing and the potential availability of building and ornamental stone resources in Tasmania, for use as blocks, veneer and paving slabs, tiles, monumental works, and in other building applications. For the purposes of this report, the term "building and ornamental stone" refers to stone used in block or slab form (ie, "dimension stone"), and as terrazzo, but not to stone used as crushed aggregate for concrete, or in other forms. This systematic evaluation of building stone potential in Tasmania should give a clear indication of the potential for a significant building stone industry. This information can be used as a basis for expanding existing stone enterprises, and for encouraging the development of new enterprises using Tasmanian stone. The potential for production of exportable stone is of particular interest. This is stone of high durability which is likely to be in high demand in virtue of having colours, textures or other aesthetic qualities which are unusual or in short supply elsewhere. More common stone varieties of high quality which are available in large quantities, easily extractable in large blocks, and in easily accessible locations, may also be exportable.