Optimal Linear Estimation (OLE) Modeling Supports Early Holocene (9000–8000 RCYBP) Copper Tool Production in North America

The discovery and development of metal as a tool medium is a topic of global interest. A fundamental research goal involves establishing the timing of human experimentation with naturally occurring copper ore, which is commonly associated with sedentary, agrarian-based societies. However, in North America, there is well-documented millennia-scale exploitation of copper as tool media by small, seasonally mobile hunter-gatherer groups in the western Great Lakes. Archaeologists have suggested that Late Paleoindian groups may have begun using copper as a tool medium almost immediately after they entered the Lake Superior basin. However, only a few radiocarbon dates support such early use of copper. Here, we use optimal linear estimation modeling to infer the origin date for copper tool production in North America. Our results show that the invention of copper as a tool media likely occurred shortly after the first pioneering populations encountered copper ore during the Pleistocene-Holocene transition. The origin dates modeled here (ca. 8100 RCYBP) reveal several important features about the behavior of pioneering hunter-gatherer populations. Moreover, our results suggest that this phenomenon represents the earliest known use of metal for utilitarian copper tool production.

The Innokenty Lopatin and Friedrich Schmidt 1866 Yenissei (‘Turukhansk’) expedition: the first evidence of discovery of Norilsk-Talnakh Cu-Ni-PGE deposits

The history of the the discovery of world’s largest Ni-Cu-PGM deposits of Norilsk-Talnakh is revised. The 1866 prospecting and geographic expedition of Innokenty Lopatin and Friedrich Schmidt, studied the lowest Yenissei territories, and collected information and mineralogical samples (chalcopyrite from ‘copper slates’) proving by this the presence of a copper ore deposit in the Norilsk mountains. The deposit was developed by at least two adits since 1865 and was managed by brothers Pyotr and Cyprian Sotnikov from the settlement of Dudino (now Dudinka). This information was documented in the diaries by I. Lopatin and was reported by F. Schmidt in transactions of the Saint Petersburg Academy of Sciences. After the ‘re-discovery’ of the deposit in the 20th century the followers have ignored, omitted and incorrectly cited the information published by Friedrich Schmidt in 1869 and 1872, as well as its republishing made by Vladimir Obrutchev in 1917. The real sequence of events resulting in the discovery of Norilsk deposits has to be rewritten. In memoriam of Sergey Gorbunov (1952–2021), archaeologist, traveler, Sakhalin history specialist

Numerical analysis of the transport of brine in the Odra River downstream of a mine's discharge

The mining of underground deposits causes the inflow of water to workings and the necessity of pumping them to the surface. The mining plant of KGHM Polska Miedź S.A. extracts copper ore in plant branches with different hydrogeological conditions. The inflowing water into the workings is characterised by variable mineralisation, which depends on the location of the branch. In the south-western part of the deposit, a low-mineralised stream with a relatively high flow rate can be observed, while the outflow of highly saline waters occurs in the north-eastern branch. Despite the activities undertaken that aim at using the pumped-off mine waters industrially, it is necessary to deposit them into the Odra River. Reducing the environmental impact on the Odra River is one of KGHM's goals, which is being implemented by stabilising its salt concentration at a safe level. The paper presents the results of a 3D simulation of brine plume propagation based on a numerical model of advection–diffusion and turbulent flow. Bathymetric data from a section of the river approximately 500 m long and point data from an Odra water quality test were used to develop and validate the model. The paper discusses the types of factors that minimise the impact of brine discharge. The developed model will be used in the future to propose solutions that accelerate the mixing of mine waters with the waters of the Odra River.

Practical Use of Measuring the Deflection of Roof Layers in the Assessment of the Stability of Mining Excavations in the Polish Copper Ore Mine “Polkowice-Sieroszowice”

The paper presents the results of long-term continuous measurements of the deflection of the roof layers in the underground copper mine Polkowice-Sieroszowice, Poland belonging to KGHM Polska Miedź S.A. The measurements were performed with the use of the inclinometric method consisting of continuous registration of changes in the angle of inclination of the roof strata. The measurements were carried out using an inclinometer sensor fixed to the end of a rockbolt in the roof. Measurements presented in the article were made in various regions of the underground mine. The monitoring covered: The exploitation front, machinery chamber and the region of the experimental longwall mining of copper ore. The obtained results proved the usefulness of the developed method in the process of the evaluation of the stability of mining excavations. The sensors were highly sensitive and performed the measurements in a simple way; highly accurate and reliable results were obtained.

A Remote-Sensing-Based Alteration Zonation Model of the Duolong Porphyry Copper Ore District, Tibet

Remote sensing (RS) of alteration zones and anomalies can provide information that is useful for geological prospecting and exploration. RS is an effective method for porphyry copper mineral exploration and prospecting prediction. More specifically, the Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER) data, which include 14 spectral channels from visible light to thermal infrared, are useful in such cases. This study uses visible-shortwave infrared and thermal infrared ASTER data together with surface material spectra from the Duolong porphyry copper ore district to construct an RS-based alteration zonation model of the deposit. In this study, an RS alteration zoning model is established based on ground-spectral alteration zoning results. The methods include PCA (Principal Component Analysis), Ratio, and Slope methods. The information obtained by each method is different. RS-based alteration zonation is developed based on the intersection of maps, resultant from the different methods for extracting information related to different minerals. The alteration zonation information extracted from ASTER RS data is consistent with geological observations. Using information from the RS-based model, we mapped the alteration minerals and zones of the Duolong ore district, thereby identifying prospecting target areas of the deposit.

Experimental Study of Operational Parameters on Product Size Distribution of Tumbling Mill

To assess the effects of the mill operating parameters such as mill speed, ball filling, slurry concentration and slurry filling on grinding process and size distribution of mill product, it was endeavored to build a pilot model with smaller size than the mill. For this aim, a pilot mill with 1 m × 0.5 m was implemented. There are 15 lifters with 50 mm height and face angle of 30˚. In the present work, the combination of the balls (40% of the balls with 60 mm diameter, 40% of the balls with 40 mm diameter and 20% of the balls with 25 mm diameter) was used as grinding media with 10%, 15%, 20% and 25% of the total volume of the mill. The experiments were carried out at 60%, 70%, 80% and 90% of the critical speed. The feed of the mill is copper ore with the size smaller than 25.4 mm, which d80 and d50 of them are 12.7 and 8 mm, respectively and slurries with 40%, 50%, 60%, 70% and 80% of solid and the slurry filling between 0.5 and 2.5. The results showed that the best grinding and grading occurs at 70–80% of the critical speed and ball filling of 20–25%. Optimized grinding was observed when the slurry volume is 1–1.5 times of the ball bed voidage volume and the slurry concentration is between 60% and 70%. The mill grinding mechanism in this work is a combination of both impact and abrasion mechanisms.

Supergene Copper and the Ancient Mining Landscapes of the Atacama Desert: Refining the Protocol for the Study of Archaeological Copper Minerals through the Case Study of Pukara de Turi

Northern Chile is home to the world’s largest copper ore deposits, which have been exploited for thousands of years by different groups, at varying scales and for different purposes. In this context, it is important to develop new protocols to characterise the mineralogical variability of archaeological copper ores. A comprehensive and representative methodology in the analysis of minerals, the application of non-destructive analytical techniques, and the combination of insights from geological, archaeological and local knowledge are key to developing a copper mineral repository of the Atacama Desert area. Geochemical analyses were applied to the study of 568 samples from the archaeological site Pukara de Turi, with different techniques such as micro-XRF, XRD, QEMSCAN, Raman spectroscopy and technological studies. This exhaustive analysis allowed for the recognition of two mineralogical associations: atacamite/brochantite (99%) and azurite/chrysocolla (1%). The study of various minerals allows data to be interpreted more reliably and to trace the likely geological sources of these minerals. The azurite/chrysocolla samples appear to belong to the same mineral association found in the Cerro Verde district, which is probably the source of these samples. The atacamite/brochantite samples appear to come from more than one geological source, including, but not limited to, Chuquicamata-Radomiro Tomic and El Abra-Conchi.