Henrique Garcia Pereira

Deep-sea Fe-Mn Crusts from the Northeast Atlantic Ocean: Composition and Resource Considerations

Eighteen deep-sea ferromanganese crusts (Fe-Mn crusts) from 10 seamounts in the northeast Atlantic were studied. Samples were recovered from water depths of ∼1,200 to ∼4,600 m from seamounts near Madeira, the Canary and Azores islands, and one sample from the western Mediterranean Sea. The mineralogical and chemical compositions of the samples indicate that the crusts are typical continental margin, hydrogenetic Fe-Mn crusts. The Fe-Mn crusts exhibit a Co + Cu + Ni maximum of 0.96 wt%. Platinum-group element contents analyzed for five samples showed Pt contents from 153 to 512 ppb. The resource potential of Fe-Mn crusts within and adjacent to the Portuguese Exclusive Economic Zone (EEZ) is evaluated to be comparable to that of crusts in the central Pacific, indicating that these Atlantic deposits may be an important future resource.

Assessment of the Impact of Pollution by Arsenic in the Vicinity of Panasqueira Mine (Portugal)

The mining and beneficiation processes at Panasqueira mine have given rise, during a long production period, to a large amount of sulphide-rich waste, contained in several tailing ponds, two of them located near a small village. Among the pollutant elements that occur in the surrounding area, arsenic (AS) was selected to illustrate a geostatistics based methodology aiming at combining land use with the spatial distribution of the contaminant concentration in soils, by taking the former as an external drift to estimate the latter. Since land use is an ordinal variable, its combination, via the external drift algorithm, with As concentration requires its prior transformation into a real number. The proposed transformation relies on the Correspondence Analysis (CA) of the contingency table crossing classes of As concentration with classes of land use. The co-ordinates of samples projection onto the CA first axis turned out to be a reliable proxy of the interaction between As concentration and land use, providing the required real variable to be used as external drift. Hence, ‘raw’ As concentration maps were ‘corrected’ through the external drift algorithm, leading to an increase where land use is more ‘valuable’ (populated areas) and to a decrease where land use is less ‘valuable’ (barren soil). Obviously, the ‘corrected’ maps are a more realistic basis for reclamation planning than the ‘raw’ ones.

Discrimination of gossans using principal components analysis of standardized data

Abstract The results of a study involving geology, geochemistry, mineralogy and exploratory statistical analysis of data for a set of gossans located in the south of Portugal are presented. The objective of the case study is to demonstrate how to complement data concerning the mineralogy and geochemistry of gossans with a multivariate statistical method — Principal Components Analysis of Standardized Data — in order to discriminate gossans according to their geological environment. Moreover, a test was carried out in order to assess how summary measures for characteristic variables of each gossan compare (in this case, means versus robust estimates as medians).

A New Kind of Art [Based on Autonomous Collective Robotics]

The paper addresses the rationale of a process that produces artworks made by a swarm of robots. This process relies on the interaction, though the environment, of a set of robots designed to create spatiotemporal patterns from an initial homogeneous medium (the canvas). Inspired by social insect societies, the approach presented here exploits robot-robot and robot-environment interactions to develop emergent behaviour. The swarm intelligence concept is crucial to this approach because the viability of the team (group of robots) is required in order to achieve the viability of the individual. Without any central coordination or plan, the group of robots produces its artworks on the basis of a data-driven (bottom-up) process. Moreover, each robot can be viewed as an autonomous agent because it has on board all the resources required to provide the global outcome of the experiment, including sensors, actuators, and the controller, which demonstrates a reactive behaviour by reinforcing a previously made signal (positive feedback). The process is also presented in the context of Machine Art, and a detailed technical description of each robot is given, as well as an example of artworks produced by the collective behaviour of the set of robots.