Mining & Exploration Geology

Nanjizal is one of the few locations in the southern segment of the Land’s End Granite (Early Permian) where magmatic-hydrothermal
tin mineralization has been worked. Three principal mineralization episodes are recognized. The first episode comprises steeply
dipping ENE-WSW striking tourmaline ± quartz veins precipitated from magmatic-hydrothermal fluids during regional NNW-SSE
extension; they are not associated with metalliferous mineralization. The second episode is represented by two sets of vertical/subvertical
tourmaline veins striking, respectively, 280° and 340°. The NNW striking set hosts tourmaline-quartz-cassiterite (± alkali
feldspar, apatite, zircon) mineralization and was worked for tin during the 19th Century. The first generation of tourmaline in these
veins is dominated by the Mg-rich end-member, dravite. The subsequent two generations of tourmaline are dominated by the Ferich
end-member, schorl, together with zoned cassiterite with Fe-rich cores and Fe-poor rims. The NNW striking tourmaline-quartzcassiterite
veins at Nanjizal have a similar orientation to cassiterite-bearing veins within the St. Just Mining District further north. It
is possible that the mineralization at Nanjizal was contemporaneous with mineralization in the St. Just Mining District and hence related
to a later magmatic episode and the renewed release of magmatic-hydrothermal fluids during ENE-WSW extension. The third
mineralization episode is dominated by steeply dipping WNW-NNW striking quartz-limonite-chalcedony veins that are associated with
wall rock hematisation and kaolinisation. Schorl-quartz-cassiterite mineralisation is relatively uncommon in S.W. England but there
are remarkable similarities between the vein parageneses at Nanjizal and the Birch Tor-Vitifer area of Dartmoor; both are likely to
have been sourced from predominantly magmatic-hydrothermal fluids.

The minerals exploration sector is under strain. Junior explorers have struggled to raise funds, whilst explorers within larger companies have found budgets cut, or their roles eliminated entirely. Greenfields  exploration, which is perceived to be higher risk, has been particularly badly affected. In part, this is a response to negative external market factors. However, the exploration sector has also often provided unattractive returns, struggling with falling discovery rates, falling discovery quality and increased discovery costs. In addition, the exploration sector has faced newer challenges relating to environmentalism, native title, sustainable development and ‘social licence to operate’. As such, explorers have found that the opportunities of globalisation have been more limited than expected. It is, therefore, worth outlining the traditional business case for exploration, in particular, greenfields exploration, before considering a renewed business case for exploration that is better able to take on the challenges of the ‘social licence to operate’. The aim of this review is to help the exploration sector outline to investors and corporate parents why they should fund greenfields minerals exploration and related research activities.

El muestreo de sedimentos es uno de los métodos más  ampliamente utilizados en los levantamientos geológicos regionales y las búsquedas orientativas. Sin embargo, no existe un criterio unificado sobre cómo preparar las muestras para los análisis existiendo en la actualidad dos vías de preparación: la húmeda y la seca.
La vía seca es la más comúnmente utilizada, pero la vía húmeda tiene también sus defensores.
En este trabajo comparé estadísticamente ambos métodos usando pruebas de analogía así como el cálculo de algunos parámetros de comparación entre los dos métodos.
Este análisis demostró que la efectividad de ambos métodos es análoga para el grado de sensibilidad y reproducibilidad de la técnica analítica empleada (análisis espectral semicuantitativo de 18 elementos en cabina de esparcimiento en los laboratorios de la Empresa Santa Clara, Cuba, 1989), si bien la vía húmeda garantiza una muestra más libre de impurezas mecánicas artificiales y reduce la presencia de calcio, elemento sumamente “nocivo” en el análisis espectral.
Si bien este trabajo se basa en datos tomados por el autor y su grupo de trabajo hace muchos años, la validez del mensaje se mantiene razón por la cual la ofrecemos a nuestros lectores.

For a mineral resource to become a mine, not only must a geological discovery be made, the deposit must also prove economically viable, and environmentally and sociopolitically accessible. Explorers should therefore aim to find ‘undiscovered accessible reserves’. The inherent complexity and uncertainty surrounding the future means it is not possible to predict exactly what the nature of ‘undiscovered accessible reserves’ will be several decades into the future. One suggestion is that explorers should therefore aim to develop ‘multiple working hypotheses’ about the future of mining to appropriately process this complexity and uncertainty. More specifically, it is suggested that they should develop ‘multiple hypothetical reserves’ — different ideas about currently undiscovered mineral accumulations that could be extractable in the future. The Centre for Exploration Targeting ‘Future of Minerals Exploration’ scenarios program was launched with the aim of developing the idea of ‘multiple hypothetical reserves’ using the Oxford Scenario Planning Approach. The initial results of the program are summarised below.

THE TRUE HISTORY OF INVISIBLE (EPITHERMAL)  GOLD
IN  SOUTHERN TUSCANY (AND LAZIO)

After having had contact with an Italian-Canadian geologist (Giacarlo Facca), author of an article on Carlin-type epithermal gold published in “Le Scienze” May 1982, I begun explorations in southern Tuscany  and immediately highlighted  the presence of alluvial gold in some rivers.  Then, thanks to analyzes of collected samples,  carried out by Cominco Resources of Vancouver  in 1984, I highlighted the presence of small gold contents in some of the Tuscan antimony old mines. My report to various research and university bodies, as well as to parastatal bodies that carried out mining explorations in the area, remained unanswered. At that time, mining explorations and exploitations, in Italy, were monopolized by the state-owned companies of the ENI group which, thanks to specific laws, received an enormous, and disproportionate, amount of public money to carry out "basic research”.  Theese were entrusted  by RiMin, a small company of the Group, headed first by SAMIM, then by AGIP Miniere. Ultimately, the explorations relied completely on academic studies commissioned to local university structures or to individual professors, with questionable scientific preparation but certainly lacking practical experience, which ended up conditioning the choices,  and managing them on the basis of their preconceived theories.

They  dictate  that all the ore deposits my have sedimentary or syn-sedimentary genesis, so it was not admissible that there could be some of volcanic origin.  And this despite the fact that, in the specific case, ephitermal gold deposits had been exploitated in America since 1965’s.

However, my personal explorations continued and, in collaboration with an Italian-Canadian colleague (Luca Riccio), we highlighted some interesting  indices, in southern Tuscany and northern Lazio, for which an Italian-Canadian mining company (Cal Denver) was set up in Italy.  In 1985 we were able to apply for some exploration permits. In fact, after years of "closure" and "research" made without construct, the parastate companies had abandoned them,  based on the conclusions of Florentine professors, authors of a definitive negative "state-of art" of Tuscan mineral deposits, still considered to be of sin-sedimentary origin.  But, following the uproar aroused by the prescribed applications publication, accompanied by my geological reports, and despite the favorable opinion of the peripheral mining administrations, the applications were blocked in Rome, and the exploration was undertaken by the same parastatal mining companies, with the collaboration of the same university consultants who, before, had a priori excluded the presence of that type of mineralization.

Following judicial controversy, Cal Denver had to settle for an agreement with Agip Canada, while I was granted modest compensation in the form of consultancy for the work that Agip Miniere had begun in southern Tuscany,  and for the explorations it intended to conduct in Sardega, for the same type of mineralization  that I had identified (and which will lead to the opening of the Furtei mine). In fact, I had extended the prospecting to all of Italy, recognizing more or less interested indices in various volcanic contexts, more or less recent.  My two publications on the subject (1985 and 1986), the first ever on the subject, provocate a decisive change of course in Italian metallogenic thinking, and something  was overlooked by the academic circles that, touched by my criticisms, not only failed to recognize it, but they tried to hide by claiming the patenity in numerous publications, followed years later by mine.
Meanwhile, the explorations of the parastal companies, in southern Tuscany and Lazio, despite drilling and analyzes enormous expenses, did not go beyond the recognition of the clues already highlighted by Cal Denver (and described in my attached reports). They had a traumatic end in 1992, with the “Tangentopoli” scandal and the start of the “Mani Pulite” judicial investigation, which, among other things, highlighted that the enormous found for mining as for other public activities, had mainly served to finance illicitly parties and politicians.

Once the research was freed from the state monopoly, investigations periodically carried out by some small foreign companies,  followed one another for years, sometimes flaunting the very high (and false) gold contents previously advertised by RiMin,  and managing the sums collected in the stock exchanges of its countries.

The aim of this research is to design and build a resistivitimeter that can perform resistivity electrical prospecting studies, which allows to calculate the resistivity of the subsoil (ρ) through the measurements of potential difference (ΔV) and induced current in the underground (I) .
The methodology used was guided by the following design process proposed by Haik and Shahin (2003): Which involves the analysis of the important technical specifications of a commercial team, main functions of a team, generation of concepts and the construction of the prototype. This is supported by geophysical concepts, in order to establish the function parameters appropriate to the designed equipment. As a final phase of the methodology, it is the observation of the readings of the potential difference (ΔV) and the induced current (I) in the terrain.
As a result of this research, we have managed to build a resistivimeter, which consists of 2 internal modules: One is the controlled direct current (DC) transmitter (TX) with the specifications: 12 V input voltage, 350 V output voltage, output current up to 1A  maximum. The other module is the receiver (RX) that performs the measurements of the potential difference (ΔV) and the induced current in the ground (I), which is displayed on a liquid crystal display (LCD).
As a result of the application in the resistivimeter field, the equipment has the capacity to perform vertical electrical soundings (SEV), the data measurements in millivolts (mV) and milliamperes (mA). In addition, it has the ability to perform Resistivity Electrical Tomography (ERT) of up to 10 levels of investigation.
Finally, as a conclusion to this research, it has been achieved to design and develop a resistivimeter to perform geoelectric measurements, with efficient characteristics, safe, economical and easy to use.

Yeraltı jeolojisi, uygulamalı jeolojinin ana faaliyet alanıdır. Bu bilim dalında gerek sığ yeraltı
koşullarının mühendislik özelliklerinin saptanması ve sınıflandırılması amacıyla, gerekse
doğal yeraltı kaynaklarının belirlenmesi ve işletme koşullarının araştırılması amacıyla
yeraltının jeolojik özellikleri doğrudan (sondaj kuyusu, galeri, yarma, kuyu, vb.) veya dolaylı
(Jeofiziksel) araştırma yöntemleri kullanılarak aydınlatılmaya çalışılır. Ayrıca, hem aktif
tektonik yapıların yüzeye yakın kesimlerdeki özelliklerinin belirlenmesinde hem de yeraltı
veya açık maden işletmelerindeki yapısal sorunları çözümlemek amacıyla yeraltı jeolojisi
çalışmaları yürütülür. Doğrudan araştırma yöntemlerinde elde edilen veriler genellikle
noktasal veriler olduklarından, bu noktasal verilerden hareketle düzlemsel veriler üretebilmek
amacıyla jeofiziksel araştırma yöntemleri geliştirilmiştir. Bu jeofiziksel araştırma yöntemleri
günümüzde oldukça çeşitlenmiş olmakla birlikte, bu kitapta bunlardan sadece üçüne yer
verilmiştir; bunlar, Sismik Yansıma Yöntemi, Elektromanyetik Profilleme Cihazı (EMProfiler)
ve Yer Radarıdır.

In mining operations carried out below the water table, mine area could potentially affect the surrounding. With further deepening of the mine and quarry, the drawdown can impact on water supply wells and base flow. The variation in radius of influence under confined and unconfined aquifer condition is assessed using a hypothetical case study with three operational quarry sites. Average pit-wise radius of influence (R0) for the pit mine, under unconfined and confined aquifer conditions is 963 m and 61 km, respectively, whereas effective radius (Re) for total (cumulative) excavated mine area is 1.7 and 146 km, respectively. It means that the maximum and minimum value of overall impact/influence for the unconfined aquifer lies in-between 963 m and 1.7 km. Similarly that the maximum and minimum value of overall impact/influence for the confined aquifer lies in-between 61 and 146 km. Meanwhile, Re or effective radius for total (cumulative) excavated area seems more appropriate from evaluation viewpoint due to the overlapping (superposition) concentric mining quarries. Thus, assessment of quarry-wise and total radius of influence is of importance to fulfil targeted production, economically with minimum interruptions as part of the mine planning. Moreover, it helps us to assess, monitor and regulate the impact of a mine-dewatering program in the area. Also, the pumping test is often used to estimate radius of influence; it can trigger the inflow or radius of influence. Estimate of the radius of influence using analytical equation mainly independent of discharge/abstraction from the aquifer stands as a preferred choice for the prediction of radius of influence at the quarry/mine pit. There is a strong rationale that policies should be informed by such analytical assessment because it helps us to prevent or minimize negative impacts as part of regulation and pit-mining management and are useful tools for practitioners to design economically efficient and cost-effective in situ groundwater remediation systems, to contain contaminant plumes, to evaluate the surface–subsurface water interaction and to verify numerical models.

Copper Creek is 80 km northeast of Tucson, at the intersection of NW-SE and WSW-ENE porphyry Cu belts.  Exploration since the 1960s has partially defined a porphyry deposit at 350 to >1500 m depths, with near-surface higher grade breccias. 

Porphyry and breccia resources are hosted primarily in the 61.8-Ma Copper Creek Granodiorite, which intrudes Late Cretaceous andesite and dacite, and Proterozoic to early Paleozoic clastic and carbonate rocks and Proterozoic diabase on the southeast.  Laramide porphyries progressed from monzogranite through three phases of granodiorite porphyry (GDP1, GDP2, and GDP3) which are temporally and spatially linked to Cu-Mo mineralization.  Late porphyritic quartz diorite mixed with GDP2 and GDP3 to form hybridized rocks.  Over 400 magmatic-hydrothermal breccia bodies formed mostly between emplacement of GDP2 and GDP3.  The district is bounded by Miocene through Holocene gravels to the southwest and Oligocene-Miocene volcanic cover on the northeast.

Cu-Mo mineralization of the early halo type (Proffett, 2009) extends at least 2.1 by 1.1 km by 0.9 km vertically.  Early introduction of Cu occurred in sheeted early halo (EH) veinlets with centimeter-scale envelopes of sericite > biotite ± K-feldspar and common chalcopyrite ± pyrite.  Grades exceed 0.5% Cu where a steep ENE-striking EH vein set cuts a low-angle domal set.  A-type veinlets formed deeper in the system but contributed only minor Cu.  EH veins are cut and reopened by D-type quartz-sericite ± tourmaline ± specularite veins containing variable chalcopyrite, pyrite, bornite, molybdenite, tennantite, galena, and/or covellite.  D veins and quartz-sulfide ± tourmaline ± anhydrite breccias upgraded portions of the early halo system to >1.0% Cu.  Explored breccias are near-vertical pipes, commonly NNW-elongate, from several to 250 m across, and have been traced up to 900 m vertically.  Many are “blind” at the surface; they pinch downward into bodies of GDP2 or GDP3.  The sulfide system is 7 by 5 km in extent and zoned outward from a chalcopyrite + bornite core through zones of chalcopyrite > pyrite, pyrite > chalcopyrite, a weak (~2-3 vol%) pyrite halo, into fringing Pb-Zn-Mn-Cu-Ag-mineralized D veins.  Re-Os determinations bracket mineralization at 56.9-61.7 Ma.  Oxidation is thin and significant supergene enrichment is limited to one breccia body.  The system appears structurally intact; attitudes of breccia pipes, steep EH veins, and Tertiary volcanic rocks suggest ~10 degrees of postmineral tilting toward the NNE or NE.

Exploration for deeper porphyry mineralization in the district was historically guided by Cu-rich surface breccias, rock geochemistry, and induced polarization anomalies.  Recent work has shown, however, that the most effective technique is systematic mapping of the steep EH vein set.  The surface extent of ≥3 vol% early halos closely predicts the extent of >0.2% Cu within 350-700 m of the surface.

The study were to assess on the impacts of mining activities on land degradation, land stability, atmosphere, water resource, biodiversity and on local residents as well on local uses of mineral resources in Kape area.Data's employed were gathered through field observation, group discussion, and asking local peoples aboutimpact of gold mining, their consequences and their activities in the study area. Theoperations that practiced in the study area characterized by shallow diggings some meters depthunderground and on the surface, which follow the reefs. This activities meansriverbed gold panning creates a number of serious environmental impacts such as landdegradation, land stability, soil erosion, deforestation and impacts on both surface andsubsurface water. Because the local people gets income daily from this activities and have highdemand for gold leads to increase in mining activities which results in land use changes. Therefore,the government and its partners should make efforts to harmonize forestry and mininglaws to avoid conflicts of interest which lead to sustainable management of bothforest and mineral resources.

Experiencia en Gestión de Recursos Naturales, Caracterización Geológico-Geotécnica de Terrenos y Macizos Rocosos, Estabilidad de Taludes, Aprovechamiento y Gestión de Materiales para su puesta en Obra, Gestión de Canteras, Escombreras, Residuos y Vertederos.
Gestión de Proyectos; Obra Civil, Edificación, Exploración y Explotación Minera, Sistemas de Bombeo, Redes de Distribución de Combustibles Gaseosos, Gestión de Residuos. Asistencia Técnica de Proyectos, Seguimiento y vigilancia mediante Ensayos y Control de Calidad en Ejecución de Obras.
Conocimientos y experiencia en el manejo de Normativa y Legislación aplicables en Minería, Construcción y Medio Ambiente; Normas y Manuales; C.T.E., EUROCODES, ICAFIR, Documentos Básicos y Norma Sismo-resistente de Cimentación Estructural NSCE, P.G.-3, E.H.E., Marcado C.E., ISO 9000, Normas UNE-EN-ISO, B.S., N.L.T., A.S.T.M., NI- 43-101, JORC-Code, SAMREC y otros Protocolos de Control Qa / Qc, OHSAS 18001, Planes de Labores, Ley de Minas, R.G.B.S.M. e I.T.C.´s, ISO 14000, Ley GICA, Planes de Gestión de Residuos, EIA.
Experiencia en Acreditación de Laboratorios de Control de Calidad en distintas Comunidades Autónomas. Ensayos Destructivos y No Destructivos (Campo y Laboratorio).
Habilidades para el desarrollo de trabajos integrales, Investigación bibliográfica, Toma, Análisis y Gestión de datos, redacción de Informes Técnicos de Competencia y Calidad bajo criterios y objetivos propuestos.
Realización e Implantación de Procedimientos Técnicos en Proyectos de Investigación, Gestión de Campañas de Perforación Geológicos-Geotécnicos, Estudios Técnicos e Informes adaptados a Normativa y Legislación vigentes.

Gemstones have always been at the centre of poverty alleviation in rural areas of Mzimba, Rumphi, Chitipa, Ntcheu, Neno, Mangochi, Zomba, Mulanje, Chikwawa and Nsanje. Most of the information we have on these stones came from small prospectors who made most of the discoveries. These stones have been found in mica pegmatites, metamorphic rocks, ultramafic rocks and karoo volcanic rocks.

Field relationship, petrographical studies and geochemical analysis were combined in
investigating the depositional environment and industrial viability of limestone beds in
Purechem’s quarry at Onigbedu. Field observation indicates a homogenous lithology of the
beds with variation in textural and clastic composition. Petrographic study revealed that the
limestone falls under the Biospamicrite and Wackestone classification based on the works of
Folks, (1959) and Dunham, (1962) respectively. The geochemical analysis which involves the
use Atomic Absorption Spectrophotometer (AAS) to determine the major and minor oxides
and the LOI constituent of the six (6) limestone beds reveals that; the CaO concentrations
ranges between 48.75 and 54.24% with a mean value of 52.63%. The silica SiO2 contents range
between 1.26 – 8.33 % with a mean value of 2.98% and Fe2O3 between 0.55 – 1.11% with
mean of 0.74%, MgO and Al2O3 contents vary between 0.58 – 1.11% and 0.52 – 1.25% with
equal mean values of 0.79%. The limestone is highly fossiliferous with the identified fossils
indicating deposition in an open shelf environment. Moreover, the limestone deposit was
equally observed to be principally mud supported which is indicative of rocks deposited in
quiet water and a low energy environment, therefore from all indication, the limestone was
deposited under low to high energy condition. Interpretation of these results suggest a shallow
marine environment. The observed compositional features of the limestone makes it a very
viable industrial raw material because it certifies the specifications of the Morroccan Standard
NM 10.1.004, and the American Construction Code, in the use of limestone for various
industrial purposes.

The election of Donald Trump and the Brexit referendum herald a shift towards a tighter definition of economic value, at the expense of the broader value concept of sustainable development; as well as a rise of protectionism, reversing a long-term trend of globalisation. However, the situation is complex, especially over the longer term in which mine project development and exploration operates. The minerals sector should proceed with caution. A greater focus on the local impacts of mining may be strategically beneficial, not only to mitigate against a potential protectionist future, but also because sustainable development has become more ‘localist’ via the concept of ‘social licence to operate’, whilst globalisation also seems to provoke increased ‘localist’ sentiments (known as ‘glocalism’). Localist strategies, therefore, seem a good hedge against multiple political futures. By contrast, moving away from sustainable development appears strategically riskier. Not only are ‘unsustainable’ activities, such as pollution and civil rights infringements harder to reverse, but a movement towards a more sustainable global economy may already be predetermined, even if the journey there may seem oblique. It appears that the increased economic development that is coveted globally is intrinsically linked to a rise in environmental and social consciousness.

Marble reserves are the most valuable asset of every marble company. That is why it is very important evaluation of the reserves to be undertaken in such a manner that will gave as full and precise picture of them. The Geological Department in AD Mermeren Kombina Prilep is implementing quantitative evaluation of marble according to the existing law regulations in the country and also to be compliant with the International standards for reporting on mineral resources and reserves. That's why we have established this Procedure for marble characterization.

This research focused on the mode of magnesite mineralisation within the host rocks in  Folovhodwe  deposit.  Two  hostrocks  and  the  hanging  wall  were  sampled  from Folovhodwe Mine. The investigation was undertaken to establish the way magnesite was  formed  within  the  hostrocks.  The  study  established  the following  rock  types: basalt (hostrock), dolerite sill (hostrock) and sandstone (hanging wall), as well as the magnesite ore occurrence in the study area.
Petrographic studies and geochemical analysis were used to establish the mode of magnesite  mineralisation  within  basalt  and  dolerite  sill.  The  major  rock-forming minerals  of  basalt  are  plagioclase  and  clinopyroxene,  and  of  dolerite  are  olivine,
orthopyroxene,  clinopyroxene  and  plagioclase.  Petrographic  studies  have  shown evidence of alterations of the hostrocks through the presence of sericite,  smectite, talc and serpentine.
The geochemical analysis of the hostrocks showed lower concentrations  of MgO in basalt (3.61%) as compared to dolerite (30.75%). The analysis also indicated 51% SiO2 in basalt and 41.14% SiO2 in dolerite. Geochemical analysis also showed that
the  magnesite  ore  hosted  in  dolerite  comprised  65%  MgCO3
and  in  basalt  it  was 16% MgCO3.
The magnesite mineralisation took place along the joints, cracks and crevices within weathered  basalt  and  dolerite,  resulting  from  the  carbonation  of  forsterite  and enstatite that were altered to amphibole, serpentine and talc in the presence of CO2
and H2O to produce magnesite, smectite, palygorskite and sepiolite. Forsterite and enstatite were the primary sources of the Mg2+ ion.
The high content of olivine and pyroxene in dolerite led to the abundance of the Mg2+ ion  during  alteration,  hence,  the  dominance  of  magnesite  in  dolerite.  However, further work is recommended  to ascertain  the  role  of  temperature  and pressure  in the formation of magnesite within basalt and dolerite in the study area.

Cameroon has a strong geological potential for a number of mineral resources that, if well managed, could support economic growth. The country contains potentially large deposits of iron ore, gold, bauxite, diamond, limestone, nickel, and gemstones, and indices of other numerous minerals and precious metals. Despite its geological wealth, mining has never played a major role in Cameroon's economic development. A study on the state of sustainable development and environmental challenges in the Cameroon mining sector permits the identification of key points for improvement in order to position the country towards achieving a sustainable mining industry in the future. This paper reviews the mining potential, stakeholder participation, legislation, and mining policy in Cameroon mining industry. The methodology involves a single case study focused on the review of sustainable development in the Cameroon mining industry up to date. It includes scientific studies, and reports of ministries and support organizations, national laws, and regulations related to the area of study. Also the corporate sustainability reports of mining companies and mining stakeholders are analyzed. This research work covers the latest developments in terms of the institutional and regulatory frameworks for mining and the environment in the country, history of mining in Cameroon, and evolution and issues of the Environmental and Social Impact Assessment (ESIA) system in the mining sector until 2016. The work concludes with an identification of the current challenges of implementing sustainable development in mining as well as future directions that research works on this area should take.

Monazite [(Ce, La, Th, Nd, Y) PO4] occurs far more widely within the magmatic hydrothermal lode systems of Cornwall than has been
previously recognised. In situ and mine dump specimens analysed by binocular and transmitted light microscopy, SEM, XRD and
whole rock XRF reveal a near ubiquitous association of hydrothermal monazite with polymetallic chlorite-(tourmaline)-quartz-
(fluorite)-cassiterite-sulphide mineralisation. The assemblage is interpreted to represent an early lode paragenesis formed by mixing
of magmatic hydrothermal fluids with meteoric and/or metamorphic fluids derived from the country rocks. Such a model may explain
why these assemblages are not observed in mines that have worked at greater depths within the granite. Major advances in
understanding the chronology of granite magmatism across SW England using U-Pb monazite and xenotime methods have not, to
date, been matched by the same level of success with respect to the development of the productive major lode systems. This discovery
of widespread hydrothermal monazite raises the potential for high precision U-Pb dating of such mineralisation across the Cornubian
Orefield. Where paragenetic relationships can be established it may also be possible to construct a fine-scale chronology for individual lode systems.