diff --git a/calculate_average_coolmineman.sh b/calculate_average_coolmineman.sh
new file mode 100755
index 0000000..cabd0c4
--- /dev/null
+++ b/calculate_average_coolmineman.sh
@@ -0,0 +1,30 @@
+#!/bin/sh
+#
+#  Copyright 2023 The original authors
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+#
+
+# Uncomment below to use sdk
+# source "$HOME/.sdkman/bin/sdkman-init.sh"
+# sdk use java 21.0.1-graal 1>&2
+
+source "$HOME/.sdkman/bin/sdkman-init.sh"
+sdk use java 21.0.1-graal 1>&2
+if [ -f "target/calculate_average_coolmineman.jsa" ]; then
+    JAVA_OPTS="-XX:SharedArchiveFile=target/calculate_average_coolmineman.jsa -Xshare:on"
+else
+    # First run, create the archive:
+    JAVA_OPTS="-XX:ArchiveClassesAtExit=target/calculate_average_coolmineman.jsa"
+fi
+time java $JAVA_OPTS --class-path target/average-1.0.0-SNAPSHOT.jar dev.morling.onebrc.CalculateAverage_coolmineman
diff --git a/src/main/java/dev/morling/onebrc/CalculateAverage_coolmineman.java b/src/main/java/dev/morling/onebrc/CalculateAverage_coolmineman.java
new file mode 100644
index 0000000..f2fb471
--- /dev/null
+++ b/src/main/java/dev/morling/onebrc/CalculateAverage_coolmineman.java
@@ -0,0 +1,280 @@
+/*
+ *  Copyright 2023 The original authors
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package dev.morling.onebrc;
+
+import java.nio.ByteBuffer;
+import java.nio.channels.AsynchronousFileChannel;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Paths;
+import java.nio.file.StandardOpenOption;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Set;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+
+public class CalculateAverage_coolmineman {
+
+    private static final String FILE = "./measurements.txt";
+
+    private static class MeasurementAggregator {
+        private double min = Double.POSITIVE_INFINITY;
+        private double max = Double.NEGATIVE_INFINITY;
+        private double sum;
+        private long count;
+
+        void add(double value) {
+            min = Math.min(min, value);
+            max = Math.max(max, value);
+            sum += value;
+            count++;
+        }
+
+        void merge(MeasurementAggregator o) {
+            min = Math.min(min, o.min);
+            max = Math.max(max, o.max);
+            sum += o.sum;
+            count += o.count;
+        }
+
+        public String toString() {
+            return round(min) + "/" + round(sum / count) + "/" + round(max);
+        }
+
+        private double round(double value) {
+            return Math.round(value * 10.0) / 10.0;
+        }
+    }
+
+    static class BytesKey implements Comparable<BytesKey> {
+        byte[] value;
+        int hashcode;
+
+        BytesKey(byte[] value) {
+            this.value = value;
+        }
+
+        @Override
+        public String toString() {
+            return new String(value, StandardCharsets.UTF_8);
+        }
+
+        @Override
+        public int hashCode() {
+            return Arrays.hashCode(value);
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            if (obj instanceof BytesKey bk) {
+                return Arrays.equals(value, bk.value);
+            }
+            return false;
+        }
+
+        @Override
+        public int compareTo(BytesKey o) {
+            return Arrays.compare(value, o.value);
+        }
+
+    }
+
+    static void parse(ByteBuffer a, int as, ByteBuffer b, int bs, boolean isFirst, HashMap<BytesKey, MeasurementAggregator> map) {
+        var aa = a.array();
+        var ba = b.array();
+        int pos = 0;
+        int nameEnd = 0;
+        boolean parseDouble = false;
+        int doubleStart = 0;
+        int doubleEnd = 0;
+        if (!isFirst) {
+            while (aa[pos] != (byte) '\n') {
+                pos++;
+            }
+            pos++;
+        }
+        int nameStart = pos;
+        while (pos < as) {
+            if (parseDouble) {
+                if (aa[pos] == '\n') {
+                    doubleEnd = pos;
+
+                    BytesKey station = new BytesKey(Arrays.copyOfRange(aa, nameStart, nameEnd));
+                    double value = parseDouble(aa, doubleStart, doubleEnd);
+                    MeasurementAggregator ma = map.get(station);
+                    if (ma == null)
+                        map.put(station, ma = new MeasurementAggregator());
+                    ma.add(value);
+
+                    parseDouble = false;
+                    nameStart = pos + 1;
+                    nameEnd = 0;
+                    doubleStart = 0;
+                    doubleEnd = 0;
+                }
+            }
+            else {
+                if (aa[pos] == ';') {
+                    nameEnd = pos;
+                    parseDouble = true;
+                    doubleStart = pos + 1;
+                }
+            }
+
+            pos++;
+        }
+        if (bs <= 0)
+            return;
+        for (;;) {
+            if (parseDouble) {
+                if (ba[pos - as] == '\n') {
+                    doubleEnd = pos;
+
+                    BytesKey station = new BytesKey(ofRange(a, as, b, bs, nameStart, nameEnd));
+                    double value = parseDouble(ofRange(a, as, b, bs, doubleStart, doubleEnd), 0, doubleEnd - doubleStart);
+                    map.computeIfAbsent(station, k -> new MeasurementAggregator()).add(value);
+
+                    return;
+                }
+            }
+            else {
+                if (ba[pos - as] == ';') {
+                    nameEnd = pos;
+                    parseDouble = true;
+                    doubleStart = pos + 1;
+                }
+            }
+
+            pos++;
+        }
+    }
+
+    static byte[] ofRange(ByteBuffer a, int as, ByteBuffer b, int bs, int start, int end) {
+        var aa = a.array();
+        var ba = b.array();
+        byte[] r = new byte[end - start];
+        for (int i = 0; i < r.length; i++) {
+            int pos = start + i;
+            if (pos < as) {
+                r[i] = aa[pos];
+            }
+            else {
+                r[i] = ba[pos - as];
+            }
+        }
+        return r;
+    }
+
+    static double parseDouble(byte[] b, int start, int end) {
+        boolean negative = false;
+        if (b[start] == (byte) '-') {
+            negative = true;
+            start += 1;
+        }
+        double result = 0;
+        for (int i = start; i < end; i++) {
+            if (b[i] != (byte) '.') {
+                result *= 10;
+                result += (b[i] & 0xFF) - '0';
+            }
+        }
+        if (negative)
+            result *= -1;
+        return result * .1;
+    }
+
+    public static void main(String[] args) throws Exception {
+        int pageSize = 1600000;
+        long pos = 0;
+        try (AsynchronousFileChannel fc = AsynchronousFileChannel.open(Paths.get(FILE), Set.of(StandardOpenOption.READ), Executors.newCachedThreadPool())) {
+            var cp = Executors.newWorkStealingPool(Runtime.getRuntime().availableProcessors());
+
+            var bbs = new ByteBuffer[Runtime.getRuntime().availableProcessors() * 8];
+            for (int i = 0; i < bbs.length; i++) {
+                bbs[i] = ByteBuffer.allocate(pageSize);
+            }
+
+            Future<Integer>[] futures = new Future[bbs.length];
+            HashMap<BytesKey, MeasurementAggregator>[] maps = new HashMap[bbs.length];
+            Future[] tasks = new Future[bbs.length];
+
+            for (int i = 0; i < futures.length; i++) {
+                futures[i] = fc.read(bbs[i], pos);
+                maps[i] = new HashMap<>();
+                pos += pageSize;
+            }
+
+            boolean first = true;
+            l: for (;;) {
+                for (int i = 0; i < bbs.length; i++) {
+                    int nextIndex = (i + 1) % bbs.length;
+                    if (tasks[nextIndex] != null) {
+                        tasks[nextIndex].get();
+                        bbs[nextIndex].position(0);
+                        futures[nextIndex] = fc.read(bbs[nextIndex], pos);
+                        pos += pageSize;
+                    }
+                    var fa = futures[i];
+                    var fb = futures[(i + 1) % futures.length];
+                    var isFirst = first;
+                    int ra = fa.get();
+                    if (ra < 0)
+                        break l;
+                    int rb = Math.max(0, fb.get());
+                    var iLol = i;
+                    tasks[i] = cp.submit(() -> {
+                        parse(bbs[iLol], ra, bbs[nextIndex], rb, isFirst, maps[iLol]);
+                    });
+
+                    first = false;
+                }
+            }
+
+            for (Future t : tasks) {
+                if (t != null)
+                    t.get();
+            }
+
+            for (int i = 1; i < maps.length; i++) {
+                merge(maps[0], maps[i]);
+            }
+
+            System.out.print('{');
+            boolean[] firstE = new boolean[]{ true };
+            maps[0].entrySet().stream().sorted((a, b) -> a.getKey().toString().compareTo(b.getKey().toString())).forEach(e -> {
+                if (!firstE[0]) {
+                    System.out.print(',');
+                    System.out.print(' ');
+                }
+                firstE[0] = false;
+                System.out.print(e.toString());
+            });
+            System.out.println('}');
+            System.exit(0);
+        }
+    }
+
+    static void merge(HashMap<BytesKey, MeasurementAggregator> a, HashMap<BytesKey, MeasurementAggregator> b) {
+        for (var e : b.entrySet()) {
+            if (a.containsKey(e.getKey())) {
+                a.get(e.getKey()).merge(e.getValue());
+            }
+            else {
+                a.put(e.getKey(), e.getValue());
+            }
+        }
+    }
+}