Down hole measurement system
A bore hole measurement system includes a cable with spaced apart embedded elements along a length of the cable, a sensor for detection of the elements as they move relatively past the sensor, and a processor for determining the distance that the cable has travelled based on the detections of elements that have moved past the sensor. A method includes detecting the elements moving past a sensor, and determining the distance that the cable has travelled based on the detections of elements that have moved past the sensor.
1 . A blast hole measurement system comprising:
a cable comprising equally spaced apart embedded elements along a length of the cable and comprising an outer protective layer of polyurethane or poly tetrafluoroethylene for protecting against wear damage from a blast hole, the cable comprising electrical wires surrounded by a fiber-glass layer being resistant to stretching over a depth of the blast hole;
a sensor for detection of the elements as the elements move relatively past the sensor; and
a processor for determining a distance that the cable has travelled into the blast hole based on the detections of elements that have moved past the sensor.
2 . A system according to claim 1 , wherein the cable comprises a probe at an end of the cable electrically connected to the electrical wires forming a wire core for transmitting a plurality of signals from the probe, the wire core being suitable for communication over a distance substantially the length of the blast hole, wherein the probe is configured to be lowered into the blast hole for measurement of parameters of the blast hole.
3 . A system according to claim 2 , wherein the stretch resistance fiber-glass layer comprises reinforced plastic so as to stretch less than 0.05 m per 20 m of cable length.
4 . A system according to claim 3 , wherein the probe comprises a water detector for detecting that the end of the probe is in contact with water.
5 . A system according to claim 4 , wherein the probe comprises an accelerometer and the processor is configured to determine the depth of the water based on the number of elements that have moved past the sensor between when the water detector detects that the end of the probe is in contact with water and when the accelerometer detects that the probe encounters the bottom of the blast hole.
6 . A system according to claim 2 , wherein the probe comprises a temperature sensor for measuring the air a temperature in the blast hole.
7 . A system according to claim 2 , wherein the probe comprises a distance sensor for detection of a void laterally extending from the blast hole.
8 . A system according to claim 2 , wherein the processor is configured to compare the parameters of the blast hole to requirements of a blast pattern and to determine whether the blast hole meets the requirements of the blast pattern.
9 . A system according to claim 1 , wherein the sensor is a magnetic or induction sensor.
10 . A system according to claim 1 , wherein the elements are metallic crimps around the fiber-glass layer, and underneath the outer protective layer.
11 . A system according to claim 1 , wherein the outer protective layer is in the form of a single piece extending along the length of the cable.
12 . A method of making a measurement of a blast hole comprising:
providing a cable comprising equally spaced apart embedded elements along a length of the cable;
detecting the elements moving past a sensor;
determining a distance that the cable has travelled based on the detections of elements that have moved past the sensor, without needing to account for substantial stretching of the cable when deployed in the blast hole;
determining whether a probe at an end of the cable is in contact with water using a water detector at the end of the probe;
determining when the probe encounters a bottom of the blast hole using an accelerometer in the probe; and
wherein, in the event that the water detector detects the end of the probe is in contact with water, determining a depth of the water by a number of detections of elements that have moved past the sensor between when the water detector detects the end of the probe is in contact with water and when the probe encounters the bottom of the blast hole.
13 . A method according to claim 12 , further comprising recording a temperature at the bottom of the blast hole.
14 . A method according to claim 13 , further comprising determining whether the temperature exceeds the expected temperature threshold.
15 . A method according to claim 12 , further comprising recording whether there is a void laterally extending from the blast hole.
16 . A method according to claim 15 , further comprising determining whether the recorded void in the blast hole meets the requirements of a blast pattern.
17 . A method according to claim 12 , further comprising comparing the depth of the blast hole and the depth of the water in the blast hole with requirements of a blast pattern and determining whether the blast hole meets the requirements of the blast pattern.
18 . A blast hole measurement system comprising:
a cable comprising spaced apart embedded elements along a length of the cable, the cable being resistant to stretching;
a sensor for detection of the elements as the elements move relatively past the sensor; and
a processor for determining a distance that the cable has travelled based on the detections of elements that have moved past the sensor;
wherein the cable comprises a probe at an end of the cable and an electrical wire core for transmitting a plurality of signals from the wire core, the wire core being suitable for communication over a distance substantially the length of a blast hole,
wherein the probe comprises a water detector for detecting that the end of the probe is in contact with water; wherein the probe comprises an accelerometer and the processor is configured to determine a depth of the water based on a number of elements that have moved past the sensor between when the water detector detects that the end of the probe is in contact with water and when the accelerometer detects that the probe encounters the bottom of the blast hole.