34 research outputs found
Effectiveness of interventions for preventing injuries in the construction industry: results of an updated Cochrane systematic review
Various interventions to prevent occupational injuries in the construction industry have been proposed and studied. This continuing updated Cochrane review systematically summarizes the most current scientific evidence on the effectiveness of interventions to prevent injuries associated with construction work. Search terms that covered the concepts of ‘construction workers’, ‘injury’, ’safety’ and ‘study design’ were used to identify intervention studies in five electronic databases up to April 2017. Acceptable study designs included randomized controlled trials (RCT), controlled before–after studies (CBA) and interrupted time series (ITS). In total 17 studies, 14 ITS and three CBA studies, from the US (6), UK (2), Italy (3), Denmark (1), Finland (1), Austria (1) Germany (1) Spain (1), Belgium (1) met the inclusion criteria. Most studies were at high risk of bias. There is very low-quality evidence that introducing regulations as such may or may not result in a decrease in fatal and non-fatal injuries. There is also very low-quality evidence that regionally oriented safety campaigns, training, inspections or the introduction of occupational health services may not reduce non-fatal injuries in construction companies. There is very low-quality evidence that company-oriented safety interventions such as a multifaceted safety campaign, a multifaceted drug workplace programme and subsidies for replacement of scaffoldings may reduce non-fatal injuries among construction workers
Interventions to prevent injuries in construction workers
Background
Construction workers are frequently exposed to various types of injury-inducing hazards. A number of injury prevention interventions
have been proposed, yet their effectiveness is uncertain.
Objectives
To assess the effects of interventions to prevent injuries in construction workers.
Search methods
We searched the Cochrane Injuries Group’s specialised register, CENTRAL,MEDLINE, EMBASE, PsycINFO,OSH-ROM(including
NIOSHTIC and HSELINE), Scopus, Web of Science and EI Compendex to September 2011. The searches were not restricted by
language or publication status. The reference lists of relevant papers and reviews were also searched.
Selection criteria
Randomised controlled trials, controlled before-after (CBA) studies and interrupted time series (ITS) of all types of interventions for preventing fatal and non-fatal injuries among workers at construction sites.
Data collection and analysis
Two review authors independently selected studies, extracted data and assessed study quality. For ITS, we re-analysed the studies and used an initial effect, measured as the change in injury-rate in the year after the intervention, as well as a sustained effect, measured as the change in time trend before and after the intervention
Mineral investigations in the Ben Nevis and Ballachulish areas of the Scottish Highlands
Molybdenite in the Ben Nevis igneous complex was observed by Haslam
(1965) and placed on record by Gallagher and others (1971). The purpose of the
present investigation was to examine the distribution and mode of occurrence of
the mineralisation and assess its significance
Disseminated copper-molybdenum mineralisation near Ballachulish, Highland Region
Chalcopyrite-pyrite-molybdenite mineralisation, in
disseminated, veinlet and fracture-filling forms, is
developed in adamellite and microadamellite in the
Ballachulish igneous complex. Minor scheelite is
associated with the sulphides, but is mostly confined
to the adamellite. The mineralisation occurs
sporadically over an area of at least 1800 x 800 m.
It is best developed in and around the eastern part
of the microadamellite over an area of about
250 x 450 m, where it was observed over a.vertical
interval of 250 m from the highest exposure to the
base of a borehole. An IP survey showed that chargeability
values are slightly higher in this area. The
grade is variable. In 10 ft (3 m) lengths of core, the
maximum Cu content was 264 ppm and the maximum
molybdenum content 501 ppm, but the average
tenor over the (250 x 450 m) mineralised area is
not more than 50-100 ppm Cu and lo-30 ppm MO.
Selected mineralised outcrop samples gave values of
up to 2386 ppm Cu, 9257 ppm MO, 2434 ppm W,
0.31 ppm Au and 8 ppm Ag. Rb-Sr isotopic studies
indicate that the ore minerals were deposited shortly
after emplacement of the host rocks, and it is
considered that they were introduced by a hydrothermal
system which, compared with those of
classic porphyry models, was small in extent and
weak in intensity. Sericitic alteration is generally
associated with the mineralisation, but there is no
potassic alteration evident and the standard zonation
of porphyry copper deposits is absent. There is
very little K or Rb metasomatism, the best defined
chemical change being a loss of Sr in altered rocks.
The hydrothermal fluids, as seen in fluid inclusions,
were of moderate salinity, unlike the high salinity
fluids usually characteristic of porphyry copper
deposits. Anomalously low Rb and high K/Rb values
in the unaltered microadamellite are attributed
to the separation of a Rb-rich aqueous fluid from
the microadamellite before or at the time of consolidation
of the rock. The mineralised area lies adjacent
to and northwest of a NNE-trending shatter
belt, which may have provided structural control at
depth, although at the present level of exposure the
microadamellite body appears to be the structural
control
Disseminated molybdenum mineralisation in the Etive plutonic complex in the western Highlands of Scotland
Molybdenite, mainly in quarts veinlets, ocours over an area about 5 km
in diameter within the Central Starav Granite. Although selected samples
of mineralised rock have been shown to contain up to 0.9% MO, incidence of
sulphide mineral is too sparse, even in the best areas, for a meaningful
estimate of tenor to be given. Molybdenite is usually accompanied by
pyrite. Chalcopyrite and scheelite are also widespread, though less
common. Mild hydrothermal alteration accompanies the mineralisation, but
there is no pervasive or zoned alteration, nor is there any K or Rb
metasomatism. It is suggested that the ore minerals were deposited from
hydrothermal fluids which, for lack of any structural or physico-chemical
constraints, circulated freely throughout a large volume of rock with the
consequence that the ore minerals are widely dispersed.
Within the central mineralised area, the Central Starav Granite is
more evolved in composition below 650 m than above that altitude,
suggesting that present exposure may be near the original roof of the
intrusion. Most of the molybdenite mineralisation lies below 650 m and the
Co2 contents of fluid inclusions are generally higher at higher altitudes.
A drainage geochemical survey, covering most of the Etive plutonic
complex, involved the collection and chemical analysis of 428 stream
sediments and panned concentrates. The highest concentrations of MO in
stream sediment (40 - 120 ppm) came from streams draining the central
mineralised area and only this area was examined in detail.
The investigation provided no evidence for the existence of exploitable
mineral deposits at surface or for their prediction in depth. The
possible extent of the mineralised body at depth can only be tested by
drilling, but it is suggested that further examination of exposures,
collection of additional samples of vein quarts for fluid inclusion
studies, and an Induced Polarisation survey would provide more information
about mineralisation at and near the surface and might help to define a
target for drilling
Miscellaneous investigations on mineralisation in sedimentary rocks
Five areas on the outcrop of the Helsby Sandstone
Formation (formerly Keuper Sandstone) and
Tarporle y Siltstone (formerly Waterstone)
(Warrington and others, 1980) coinciding with
known mineralisation were selected as targets for
a geochemical investigation. About 3750 soil
samples were collected and analysed for copper,
lead, cobalt and nickel. Geochemical maps are
presented to show the occurrence and distribution
of anomalous values.
In all the five areas investigated the geochemistry
of the soils identified the known areas
of mineralisation. In several instances other small
areas were also indicated where the soil values are
anomalously high and are presumed to reflect
local, hitherto unknown, mineralisation. None of
these areas, however, appear to have the area1
extent necessary for economic deposits.
The results of this preliminary investigation
indicate that in all cases the mineralisation is very
closely associated with permeable and porous
sandstone units which are faulted against less
permeable units forming trap structlzres for migrating
mineralising fluids
A geochemical drainage survey of the Preseli Hills, south-west Dyfed, Wales
A geochemical drainage survey at a density of 1 sample
per km2 was carried out across the Preseli Hills, southwest
Dyfed. Stream sediment, water and panned concentrate
samples were collected from each of 358 sites,
and Cu, Pb, Zn, Ba, Fe, Mn, Co, Ni, V, Cr, B, Zr, As, MO
and Sn were determined in sediment, Cu, Pb, Zn, Ba, Fe,
Mn, Ti, Ni, Sn, As, Ca, Ce, Sr, Sb, Zr, U and MO in
panned concentrate and Cu and Zn in water.
From a study of regional variation patterns and
multivariate statistical analysis, the main sources of
geochemical variation in the data were found to be
bedrock lithology, mineralisation, contamination and
hydromorphic processes. Strong geochemical signatures
were shown by dolerite intrusions and by acid volcanics
of the Fishguard Volcanic Group. Dark mudstones of the
D. murchisoni Beds and Sealyham Volcanic Series also
showed characteristic geochemical features whose
impact was limited by their restricted and sinuous outcrops.
A feature of most of the area is the presence of
monazite nodules, generating high levels of rare earth
elements and uranium in the panned concentrates. These
are particularly high over the Llandeilo-Ashgill sedimentary
rocks.
Geological thresholds were established using cumulative
frequency plots and percentile division. Anomalies
due to contamination could be discriminated satisfactorily
from those arising from mineralisation only by field
observation and mineralogical examination of panned
concentrates. In major streams crossing lowland areas
and in the vicinity of roads, widespread contamination
proved to be the source of most large base metal
anomalies.
Anomalies related to known mineralisation are
located in the southeast of the area, around Llanfyrnach
in the Taf valley. Anomalies reflecting hitherto unrecorded
bedrock mineralisation may be present in the
following areas:
a1
b)
cl
d)
Llanfyrnach; anomalies for Cu, Pb, Zn and Ba are
more extensive than can be accounted for by the
known vein mineralisation. High levels of other elements
suggest an association with shales.
Crosswell-Crymmych; barium and base metal anomalies
are associated with the Fishguard Volcanic Group
and overlying pyritiferous dark mudstones of the D.
murchisoni Beds. The geological setting of these
rocks, deposited in a sulphurous environment on the
flanks of an acid volcanic pile, suggests that massive
sulphide deposits are a possible target here. Locally,
weak arsenic anomalies, old trials and ancient mining
records suggest that there is also some potential for
Au mineralisation associated with pyrite in veins and
mudstones.
Minas Dinas and Pentre Ifan; small amounts of gold
and chalcopyrite were found in panned concentrates.
Very small amounts of cassiterite were found in
panned concentrates from several localities, but no
source was readily identifiable.
The anomalies in the Llanfyrnach and Crosswell areas
were considered to. merit more de tailed
are the subject of further work by BGS.
investigatio
A geochemical survey of part of the Cheviot Hills and investigations of drainage anomalies in the Kingsseat area
The results of a reconnaissance geochemical drainage Introduction
survey across an area of 850 km2 in the Cheviot Hills are
reported. At each of the 708 sample sites, the - 0.15 mm
fraction of the stream sediment, a panned heavy mineral
concentrate derived from the - 2 mm fraction of the
stream sediment and a water sample were collected. Be,
B, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Zr, MO, Sn, Ba,
Ph and Lo1 were determined in stream sediment samples;
Ti, Mn, Fe, Ni, Cu, Zn, As, Sr, Zr, MO, Sn, Sb, Ba, Ce,
Pb, Bi and U in panned concentrate samples and Cu, Zn
and Pb in water samples.
The survey area is composed largely of andesitic
volcanic rocks of Lower Devonian age. Underlying _
Silurian greywackes and shales and overlying Devonian
and Carboniferous sedimentary rocks and basaltic lavas
are exposed around the periphery of the volcanic complex.
The Cheviot granite crops out on the eastern margin
of the area.
Anomalous concentrations of metals recorded in the
drainage samples are, in general, related to (i) known
mineral occurrences, (ii) hydrous oxide precipitation and
scavenging processes, (iii) the relatively _ widespread
occurrence of baryte, (iv) contamination, (v) tourmalinisation
and other hydrothermal activity and (vi) high
background levels in unmineralised rocks. At several
localities, however, the source of an anomaly is uncertain
and some of these may reflect hitherto unknbwn mineralisation.
Anomaly groupings and regional variation patterns
in the data are influenced by major structures such
as the Gyle-Harthope fracture zone.
Follow-up investigations into a wide range of metal
anomalies in the the Kingsseat area involved more detailed
drainage sampling, geological mapping at 1: 10 000
scale and petrographic, mineralogical and lithogeochemical
studies. Rocks, previously mapped as extrusive
mica felsites, are reinterpreted as a high level intrusion
complex, named the Cock Law Complex, which contains
live distinct types of porphyry. Many of the intrusive and
extrusive rocks are highly altered and seven alteration
assemblages are identified, arising from sericitisation,
kaolinisation, silicification, tourmalinisation, haematisation
and carbonate alterations. All except haematisation
are related to Lower Devonian igneous activity. Metal
enrichments were recorded in many of the analysed rocks.
The greatest enrichments, for the widest range of
elements, occur in samples taken from a gossanous structure,
where the mineralisation has features in common
with the epithermal precious-metal style of mineralisation
associated with sub-aerial volcanism
Copper-bearing intrusive rocks at Cairngarroch Bay, south-west Scotland
Two intrusion complexes, the Bay and the Glen,
probably representing an early phase of the
Devonian magmatic episode, and a number of
dykes, are emplaced within a folded succession of
Silurian sedimentary rocks at Caimgarroch Bay.
Only the roof of the Bay Complex, which consists
of microtonalite and granodiorite, is exposed.
The Glen Complex, of uncertain form, comprises
quartz porphyry, porphyritic quartzmicrodiorite
and quartz-microdiorite. Exposure is good along
the shore line, but much of the area is covered in
thick, dmmlinised drift.
Local high chargeability zones were identified
along three geophysical traverse lines. Soil samples
were collected on a 50 m grid over the area of IP
anomalies. In addition, water, base of slope talus,
and rock samples were chemically analysed
Both the intrusion complexes and some of the
sedimentary rocks show locally intense hydrothermal
alteration. In the Bay Complex narrow
zones of bleached rock are rich in calcite, chlorite
and pyrite and contain minor chalcopyrite and
pyzrhotite. The Glen Complex displays network
fracturing, brecciation and locally intense alteration
to sericite or calcite. There is locally abundant
pyrite in veins and disseminated and rare chalcopyrite.
Arsenopyrite is present in wall rock adjacent
to the Bay Complex.
Rock geochemistry indicates a pervasive but
patchy Cu-Fe-As-MO mineralisation in all rock
types, with copper enrichment greatest in the Bay
Complex where the highest level recorded is over
600 ppm Cu. The mineralisation is accompanied
by irregular barium, potassium and strontium
enrichment. The K/Rb ratios suggest that the
hydrothermal liquors were not entirely late
magmatic. The mineralisation and alteration have
some characteristics of a porphyry system and it
is conceivable that copper enrichment might
increase with depth